This post will feature some more number pairs / number bonds activities as well as ideas for informal assessment (along with some FREEBIES). See the previous post for Part 1. Also, here is another cool virtual manipulatives site: https://toytheater.com/category/teacher-tools/ You will find lots of materials for students to use to help with these activities: counters, bears, two-color counters, whole-part-part templates, Rekenreks, etc. Check it out!
For all of these activities, the student should be working with the number of manipulatives to match their focus number. They should do several different activities using that same amount to get lots of different experiences making the same number pairs repeatedly. After a generous amount of practice, assess the child and move to the next number when ready. An important feature of each activity is for the student to verbalize the combination being made. Using a sentence frame they can have with them or putting it on the board for all to see is a plus: “____ and ____ makes _____.” Students will usually need reminders that you should hear them saying this. It takes if from just playing to being cognizant this is a serious math activity.
Heads or Tails: Use coins and a whole-part-part template. The student shakes and gently drops some coins (stick to one type of coin). Then sort according to how many landed on heads vs. tails by placing them on one of the templates. Say the combination outloud: “5 heads and 2 tails makes 7.” Repeat. Here’s a FREE Coin Toss recording sheet.
Paper Cups:The student finds different ways to place small paper cups up or down to match their focus number. Example: To make 7 I could have 5 up and 2 down, or 6 up and 1 down, or 4 up and 3 down, etc.
Hiding or “Bear in the Cave”:
Use a small bowl, clean plastic butter tub, etc. and some objects (cubes, stones, beans, cheerios, M&Ms).
With a partner and the number of objects matching the student’s focus number, partner 1 closes their eyes while partner 2 hides some of the counters under the tub and the rest outside or on the tub.
Partner 1 opens his eyes and names how many outside the tub and then tries to determine the number hiding.
Partner 2 can then reveal if partner 1 was correct or not.
Calling it “Bear in the Cave” was the idea of a math specialist I follow and clicking on this link will take you to her site with the opportunity to get the directions and recording sheet (Math CoachsCorner: mathcoachscorner.com Bears in the Cave freebie)
Be sure when students are playing that they say the number pairs outloud such as, “3 and 4 make 7.”
Roll and Cover Game / Four in a Row:
Items needed: A blank grid template (4×4 or larger), counters or crayons for each player (up to 3), and one of the following to create numbers needed to play (spinner, number cards, custom dice).
With the grid template, create the game board by randomly placing all of the numbers making up the number pairs for the focus number and fill up the grid. If working on number pairs of 6 as pictured, place these randomly: 0, 6, 5, 1, 2, 4, and 3
Using a spinner, custom dice, or number cards, select the first number (example 5). Make this sentence frame: “2 goes with ____ to make 6.” Locate the missing number on the grid and put a counter there (or color if using a printed worksheet). How to create an easy spinner: Draw one with the number of spaces needed and duplicate for multiple students. To use, students place a pencil vertically on the center of the spinner to hold a paper clip at the center. Spin the clip.
The object is to try to get 4 of your counters (or colors if using a worksheet) in a row (vertically, horizontally, or diagonally). Blocking your opponents may be necessary to keep them from getting 4 in a row.
Stories: Students can create stories using pictures from clip art or other art work:
6 children and 1 adult = 7 OR 4 girls and 3 boys = 7 Or 2 pink shirts + 5 other shirts = 7
This page can be used to record a student’s mastery of the number pairs / bonds. On all assessments, observe if student names hiding amount immediately (meaning fact is known) or uses fingers or other counting methods such as head-bobbing, etc. For mastery, you want the student to be able to name the missing amount quickly.Click here for free PDF copies: Number Bond Assessment by CE and Number Pairs assessment class recording sheet CE
The Hiding Game above can also be used as an assessment as the teacher controls how many showing / hiding. Ask the same questions each time: “How many showing?” and “How many hiding?”
Folding dot cards: Hold one flap down and open the other. Ask, “How many dots?” Then ask, “How many hiding?”I got these free at one time from www.k-5mathteachingresources.com, but not sure they are available now. At any rate, they look easy to make.These are also good to practice with a partner.Here is a similar one I made for FREE with the PDF copy :Number Bond 3-10 assessment in part-whole format
Whole-Part-Part Template: Using a circular or square template, place a number or objects in one of the parts. Ask student how many more are needed to create the focus number. This can also be done with numbers only as shown in this picture.
Let us know if you have tried any of these, or if you have others that you’d like to share!
As I’ve mentioned before, as a consultant I am available to help you as an individual, your grade level team, or your school via online PD, webinar, or just advice during a Zoom meeting. Contact me and we can make a plan that works for you. If you are interested in tutoring during your “spare time” check out my link for Varsity Tutors on the side bar. Mention my name and we both get a bonus. Have a wonderful, SAFE week. Mask up for everyone!
Learning the combinations for numbers (number pairs / numbers bonds) is critical for both operations — addition and subtraction. This is slightly different than fact families, but it’s related. With number bonds, students learn all of the possible ways to combine 2 numbers for each sum. Think of whole / part / part. If five is the whole amount, how many different ways can it be split or decomposed? For example these combinations illustrate ways to make 5:
5 = 1 and 4 (also 4 and 1)
5 = 2 and 3 (also 3 and 2)
5 = 5 and 0 (also 0 and 5)
Knowing these combinations will aid a student’s understanding of the relationship of numbers as they also solve missing addend and subtraction problems. For example:
For the problem 2 + ___ = 5. Ask, “What goes with 2 to make 5?”
For the problem 5 – 4 = ____. Ask, “What goes with 4 to make 5?”
I suggest students work on just one whole number at a time and work their way up with regard to number bond mastery (from 2 to 10). You may need to do a quick assessment to determine which number they need to start with (more of assessment both pre and post coming in Part 2). Once a student demonstrates mastery of one number, they can move on to the next. It is great when you notice them start to relate the known facts to the new ones. Here are a few activities to practice number pairs. They are interactive and hands-on.
One more thing: PreK and KG students could work on these strictly as an hands-on practice, naming amounts verbally. Using the word “and” is perfectly developmentally appropriate: “2 and 3 make 5”. With late KG and up, they are ready to start using math symbols to illustrate the operation.
Shake and spill with 2-color counters:
Shake and Spill
Use 2 color counters. Quantity will be the number the child is working on. Shake them in your hand or a small paper cup. Spill them out (gently please). How many are red? How many are yellow? Record on a chart. Gradually you want to observe the child count the red and then tell how many yellow there should be without counting them. This will also aid a student with subitizing skills (naming the quantity without physically counting the objects). To extend the activity, you can create a graph of the results, compare results with classmates, and determine which combinations were not spilled. Click on this link for the recording sheet shown: Shake and Spill recording page
Connecting cubes: Use unifix or connecting cubes. Quantity will be the number the child is working on. Two different colors should be available. How many different ways can the child make a train of cubes using one or both colors? If working with 5, they might show this: 1 green and 4 blue; 2 green and 3 blue; 4 green and 1 blue; 3 green and 2 blue; 5 green and 0 blue; or 0 green and 5 blue. They could draw and color these on paper if you need a written response.
Use a ten frame template and 2 different colored objects (cubes, counters, flat glass stones, candy, cereal, etc.) to show all of the cominations of the number the student is working on. Using a virtual ten frame such as the one here Didax.com virtual ten frame or here Math Learning Center – Number Frames are also cool – especially if you are working from home or don’t want students to share manipulatives.
On and Off: This is similar to shake and spill above. Use any type of counters (I especially love the flat glass tones for this myself) and any picture. For my collection, I chose some child-friendly images on clip art and enlarged each one separately to fit on an 8.5 x 11 piece of paper (hamburger, football, flower, Spongebob, ice cream cone, unicorn, etc.). Put the page inside a sheet protector or laminate for frequent use. Using the number of counters the student is working with, shake them and spill above the picture. Count how many landed on the image and how many landed off the image. Like mentioned above, the goal is for the student to be able to count the # on and name the # off without physically counting them. 1st and above can record results on a chart or graph. Often just changing to another picture, the student feels like it’s a brand new game! You might also like to place the picture inside a foil tray or latch box to contain the objects that are dropped. The latch box is a great place to store the pictures and counters of math center items.
4 on and 1 off
2 on and 3 off
Graphic organizers: The ten frame is a great organizer as mentioned earlier, but there are two whole/part/part graphic organizers which are especially helpful with number pairs – see below. Students can physically move objects around to see the different ways to decompose their number.
Whole / part / part
Whole / part / part
Check out Jack Hartman’s youtube series on number pairs from 1 to 10. Here’s one on number pairs of 5: “I Can Say My Number Pairs: 5″ He uses two models (ten frames and hand signs) and repetition along with his usual catchy tunes.
Also, please check out the side bar (or bottom if using a cell phone) for links to Varsity Tutors in case you are interested in doing some online tutoring on the side or know students who would benefit from one-on-one help. Please use my name as your reference — Cindy Elkins. Want some PD for yourself? Contact me and I’ll work out a good plan to fit your needs!
Next post: More activities for learning number bonds and assessment resources (both pre- and post-). Take care!!
How often do you see students counting their fingers, drawing tally marks, or other figures to add 9? But what if they could visualize and conceptualize adding 9 is almost like adding ten, but one less? This is where the ten frame comes in handy.
To be most efficient with adding 9, help students to add 10 (or a multiple of 10) to any single digit. Example: 10 + 7, 20 + 4, 50 + 8 . . .
Show a problem such as 9 + 7 as part of your daily Number Talk. Observe and listen to how students are solving.
Introduce this strategy by showing two ten frames – one with 7 and the other with 9. Check for quick recognition (subitizing) of these amounts on each ten frame.
Move one counter from the ten frame with 7 to the ten frame with 9. This will complete it to a full ten frame. Then add 10 + 6 mentally.
The purpose is for students to visualize that 9 is just one away from 10 and can be a more efficient strategy than using fingers or tally marks.
Practice with several more +9 problems.
For 3rd and up try mental math problems such as 25 + 9 or 63 + 9. Then how about problems like 54 + 19 (add 20 and take away one)?
Can students now explain this strategy verbally?
Let’s say you had the problem 14 -9. Show 2 ten frames, one with 10 and one with 4 to show 14.
To subtract 9, focus on the full ten frame and show that removing 9 means almost all of them. Just 1 is left. I have illustrated this by using 2 color counters and turning the 9 over to a different color.
Combine the 1 that is left with the 4 on the second ten frame to get the answer of 5.
Looking at the number 14, I am moving the 1 left over to the one’s place (4 + 1 = 5). Therefore 14 – 9 = 5
Start with 14 (red)
Turn over 9 (yellow)
Move the red together
Use of the ten frame provides a concrete method (moving counters around) and then easily moves to a pictorial method (pictures of dot cards). These experiences allow students to better process the abstract (numbers only) problems they will encounter.
Last week’s focus was on using ten frames to help with students’ number sense and conceptual development of number bonds for amounts 1-10. This post will feature ways to use ten frames to enhance students’ understanding of addition and subtraction. Look for freebies and a video!
There are many addition and subtraction strategies to help students memorize the basic facts such as these below. The ten frame is a very good tool for students of all grade levels to make these strategies more concrete and visual. I will focus on some of these today.
add or take away 1 (or 2)
doubles, near doubles
facts of 10
make a ten
add or sub. 10
add or sub. 9
add or sub. tens and ones
Doubles and near doubles (doubles +1, -1, +2, or -2): If the doubles are memorized, then problems near doubles can be solved strategically.
Show a doubles fact on a single ten frame (for up to 5 + 5). Use a double ten-frame template for 6 + 6 and beyond.
With the same doubles fact showing, show a near doubles problem. This should help students see that the answer is just one or two more or less.
Repeat with other examples.
Help student identify what a doubles + 1 more (or less) problem looks like. They often have a misconception there should be a 1 in the problem. Make sure they can explain where the “1” does come from. Examples: 7 + 8, 10+11, 24+25, 15 +16, etc.
For subtraction, start with the doubles problem showing and turn over the 2-color counters or remove them.
Facts of 10: These are important to grasp for higher level addition / subtraction problems as well as rounding concepts.Continue reading →
Last time I focused on some basics about learning the number bonds (combinations) of 10 as well as adding 10 to any number. Today I want to show the benefits of making a 10 when adding numbers with sums greater than 10 (such as 8 + 5). Then I’ll show how to help students add up to apply that to addition and subtraction of larger numbers. I’ll model this using concrete and pictorial representations (which are both important before starting abstract forms).
Using a 10 Frame:
A ten frame is an excellent manipulative for students to experience ways to “Make a 10.” I am attaching a couple of videos I like to illustrate the point.
Model this process with your students using 2 ten frames.
Put 8 counters on one ten frame. (I love using 2-color counters.)
Put 5 counters (in another color) on the second ten frame.
Determine how many counters to move from one ten frame to the other to “make a 10.” In this example, I moved 2 to join the 8 to make a 10. That left 3 on the second ten frame. 10 + 3 = 13 (and 8 + 5 = 13).
The example below shows the same problem, but this time move 5 from the first ten frame to the second ten frame to “make a 10.” That left 3 on the first ten frame. 3 + 10 = 13 (and 8 + 5 = 13). Continue reading →
In the previous post, I addressed problems dealing with an additive process (join; aka SSM). In this post, I will show you some models to use for these types of problems: Separate; aka Some, Some Went Away — SSWA. I will share some models which are great for KG stories as well as templates that are helpful for intermediate students to use, especially when dealing with missing addend types.
As I previously mentioned, it is my belief that students should focus more on the verb / action in the story and not so much with the key words we often tell kids to pay attention to. Brainstorm actions that signify a subtractive process. Post it in the class. Keep adding to it as more actions are discovered. With this subtractive action, kids should quickly realize that there should be less than we started with when we take something away. Here is a FREE poster showing some of the most common subtraction action verbs. Click HERE to get your copy.
This week I will focus on subtraction problem structures. There are two types: separate and compare. I suggest teaching these models separately. Also, some part-part-whole problems can be solved using subtraction. I will refer to the same terms as in addition: start, change, result. You can also use the same materials used with addition problems: part-part-whole templates, bar models, ten frames, two-color counters, number lines, and connecting cubes.
The goal is for students to see that subtraction has different models (separate vs. comparison) and an inverse relationship with addition — we can compose as well as decompose those numbers. Knowledge of number bonds will support the addition / subtraction relationship. Here is the same freebie I offered last week you can download for your math files: Addition and Subtraction Story Structure Information The six color anchor charts shown below are also attached here free for your use: Subtraction structure anchor charts
Separate: Result Unknown
Example: 10 – 4 = ____; There were 10 cookies on the plate. Dad ate 4 of them. How many are left on the plate?
Explanation: The problem starts with 10. It changes when 4 of the cookies are eaten. The result in this problem is the answer to the question (how many are left on the plate).
Teaching and practice suggestions:
Ask questions such as: Do we know the start? (Yes, it is 10.) Do we know what changed? (Yes, 4 cookies were eaten so we take those away.) How many cookies are left on the plate now? (Result is 6.)
Reinforce the number bonds of 10: What goes with 4 to make 10? (6)
Draw a picture to show the starting amount. Cross out the items to symbolize removal.
Show the problem in this order also: ____ = 10 – 4. Remember the equal sign means the same as — what is on the left matches the amount on the right of the equal sign.
Ask your students this question: “What does the equal sign mean?” I venture many or most of them will say, “It’s where the answer goes,” or something to that effect. You will see them apply this understanding with the type of problem in which the answer blank comes after the equal sign such as in 5 + 6 = _____ or 14 – 9 = _____. This is the most common type of problem structure called Result Unknown. I was guilty of providing this type of equation structure a majority of the time because I didn’t know there actually were other structures, and I didn’t realize the importance of teaching students the other structures. So . . . here we go. (Be sure to look for freebies ahead.)
Teach your students the equal sign means “the same as.” Think of addition and subtraction problems as a balance scale: what’s on one side must be the same as the other side — to balance it evenly.
Let’s look at the equal sign’s role in solving the different addition / subtraction structures. I will be using the words start to represent how the problem starts, the word change to represent what happens to the starting amount (either added to or subtracted), and the result. In this post I will be addressing the join / addition models of Result Unknown, Change Unknown, Start Unknown and Part-Part-Whole. I will highlight the subtraction models (Separate and Comparison) next time. Knowing these types of structures strengthens the relationship between addition and subtraction.
Three of these addition models use the term join because that is the action taken. There are some, then some more are joined together in an additive model. One addition model, however, is the part-part-whole model. In this type there is no joining involved – only showing that part of our objects have this attribute and the other part have a different attribute (such as color, type, size, opposites).
Example: 5 + 4 = ____; A boy had 5 marbles and his friend gave him 4 more marbles. How many marbles does the boy have now?
Explanation: The boy started with 5 marbles. There was a change in the story because he got 4 more. The result in this problem is the action of adding the two together.
Teaching and practice suggestions:
Ask questions such as: Do we know the start? (Yes, it is 5.) Do we know what changed? (Yes, his friend gave him more, so we add 4.) What happens when we put these together?(Result is 9.)
Show the problem in this order also (with result blank first instead of last) : ____ = 5 + 4
Common questions: How many now? How many in all? How many all together? What is the sum?
Join: Change Unknown
Example: 5 + ____ = 9; A boy had 5 marbles. His friend gave him some more. Now he has 9 marbles. How many marbles did his friend give him? You could also call this a missing addend structure.
Explanation: This problem starts with 5. There is a change of getting some more marbles, but we don’t know how many yet. The result after the change is (9). It is very likely students will solve like this: 5 + 14 = 9. Why? Because they see the equal sign and a plus sign and perform that operation with the 2 numbers showing. Their answer of 14 is put in the blank because of their misunderstanding of the meaning of the equal sign.
Teaching and practice suggestions:
Ask questions such as: Do we know the start? (Yes, he started with 5 marbles.) Do we know what changed in the story? (Yes, his friend gave him some marbles, but we don’t know how many.) Do we know the result? (Yes, he ended up with 9 marbles.) So the mystery is “How many marbles did his friend give him?”
Count up from the start amount to the total amount. This will give you the change involved in the story.
Reinforce number bonds by asking, “What goes with 5 to make 9?” or “What is the difference between 5 and 9?”
Join: Start Unknown
Example: ____ + 4 = 9; A boy had some marbles. His friend gave him 4 more. Now he has 9. How many did he have to start with?
Explanation: The boy had some marbles to start with, but the story does not tell us. Then there is a change in the story when his friend gives him some more (4). The result is that he has 9.
Teaching and practice suggestions:
Ask questions such as: Do we know how many marbles the boy started with? (No, the story didn’t tell us.) Do we know what changed in the story? (Yes, his friend have him 4 marbles.) Do we know the result? (Yes, he had 9 marbles at the end.)
Count up from 4 to 9.
Reinforce knowledge of number bonds by asking, “What goes with 4 to make 9?”
This is part three in a series of strategies regarding addition and subtraction strategies. This part will focus on a variety of strategies to help toward memorization of facts, meaning automatic computation. While children are learning their number bonds (building up to 5 in KG, to 10 in first grade, and to 20 in second grade), there are other facts which cross several number bonds that students can work towards. These strategies to build mental math automaticity are highlighted below. Get some freebies in the section on doubles / near doubles.
Identity (or Zero) Property:
The value of the number does not change when zero is added or subtracted.
3 + 0 = 3
9 – 0 = 9
The answer is always zero when you take away / subtract all.
9 – 9 = 0
50 – 50 = 0
Adding 1 or Subtracting 1:
Adding 1 results in the next number in the counting sequence.
Subtracting 1 means naming the number that comes right before it in the counting sequence.
With manipulatives, lay out an amount for student to count. Slide one more and see if he/she can name the amount without recounting.
Do the same as above, but take one away from the group to see if he/she can name the amount without recounting.
Show this concept using a number line.
6 + 1 = 7; 26 + 1 = 27
7 – 1 = 6; 37 – 1 = 36
After +1 or -1 strategies are in place, then go for +2 or -2 for automatic processing.
Next-Door Neighbor Numbers:
If subtracting two sequential numbers (ie 7 subtract 6), the answer is always one because you are taking away almost all of the original amount.
Help students identify these types of problems: 8-7; 10-9; 98-97; 158-157
Guide students to writing these types of problems.
Relate these to subtracting 1 problems. If 10-1 = 9; then 10 – 9 = 1.
In Part 1 I focused on a numerical fluency continuum, which defines the stages a child goes through to achieve number sense. After a child has a firm grasp of one-to-one correspondence, can count on, and understands concepts of more and less, he/she is ready to explore part-part-whole relationships which lead to the operations of addition and subtraction. That will be the focus of this post. Read on for free number bond activities and a free number bond assessment!
One way to explore part-part-whole relationships is through various number bonds experiences. Number Bonds are pairs of numbers that combine to total the target or focus number. When students learn number bonds they are applying the commutative, identity, and zero properties. Do you notice from the chart below that there are 4 number bonds for the number 3; 5 number bonds for the number 4; 6 number bonds for the number 5, etc? And . . . half of the number bonds are actually just the commutative property in action, so there really aren’t as many combinations for each number to learn after all.
KG students should master number bonds to 5.
First graders should master number bonds to 10.
Second graders should master number bonds to 20.Teaching Methods for Number Bonds
Six is 5 and 1. Six is 3 and 3. Or the child may see the bottom as 4 and 2.
Ideally, students should focus on the bonds for one number at a time, until mastery is achieved. In other words, if working on the number bond of 3, they would learn 0 and 3, 3 and 0, 1 and 2, 2 and 1 before trying to learn number bonds of 4. See the end of this post for assessment ideas.
Ten Frame cards: Use counters to show different ways to make the focus number. (See above example of 2 ways to show 6.) Shake and Spill games are also great for this: Using 2-color counters, shake and spill the number of counters matching your focus number. See how many spilled out red and how many spilled out yellow. Record results on a blank ten-frame template. Repeat 10 times.
Number Bond Bracelets: Use beads and chenille stems to form bracelets for each number 2-10. Slide beads apart to see different ways to make the focus number.
Reckenreck: Slide beads on the frame to show different combinations.
Part-Part-Whole Graphic Organizers: Here are two templates I like. Start with objects matching the focus number in the “whole” section. Then move “part” of them to one section and the rest to the other section. Rearrange to find different bonds for the same focus number. Start students with manipulalatives before moving to numbers. Or use numbers as a way for students to record their findings.
7 is the “focus number”
1 and 6 are bonds of 7
Sample recording page
Once students have a good concept of number bonds, these part-part-whole organizers are very helpful when doing addition and subtraction problems (including story problems) using these structures: Result Unknown, Change Unknown, and Start Unknown. Children should use manipulatives at first to “figure out” the story.
Here is an example of a change unknown story: “I have 5 pennies in one pocket and some more in my other pocket. I have 7 pennies all together. How many pennies in my other pocket?” To do this, put 5 counters in one “part” section. Count on from 5 to 7 by placing more counters in the second “part” section (2). Then move them all to the whole section to check that there are 7 all together. Students are determining “What goes with 5 to make 7?” 5 + ___ = 7
Here is an example of a result unknown subtraction story: “Mom put 7 cookies on a plate. I ate 2 of them. How many cookies are still on the plate?” To do this start with the whole amount (7) in the large section. Then move the 2 that were eaten to a “part” section. Count how many are remaining in the “whole section” to find out how many are still on the plate? 7 – 2 = ____.
How are number bonds related to fact families? A fact family is one number bond shown with 2 addition and 2 subtraction statements. Ex: With number bonds 3 and 4 for the number 7, you can make 4 problems: 3 + 4 = 7; 4 + 3 = 7; 7-3 = 4; and 7-4=3.
To be able to add and subtract, students normally pass through several phases as they build readiness for these operations with numbers. As teachers, we know oral counting does not necessarily indicate an understanding of numbers and sets, just like reciting the alphabet doesn’t necessarily mean a child can recognize letters and sounds. Read ahead for freebies in the Part-Part-Whole section.
Numerical Fluency Continuum: There are 7 steps to numerical fluency. If a child gets stuck on any of these steps, it may very likely halt their progress. Hopefully children move through these by the end of 2nd grade, but many students beyond that level have a breakdown which is likely because they missed one of these stages. Can you determine which of these stages your students are in?
One-to-one correspondence: The ability to count objects so each object counted is matched with one number word.
Inclusion of set: Does a child realize that the last number counted names the number of objects in the set? A child counts 5 objects. When you ask how many, can they state “5.” If you mix them up after they just counted them, do they realize there are still 5?
Counting on: If a child counts 5 objects and the teacher then puts 2 more objects for the child to count, do they start all over or continue counting from 5? 5 . . . 6, 7.
Subitizing:Recognize an amount without physically counting (ie on dice, dot cards, fingers).
More Than / Less Than / Equal To: Can a child look at two sets of objects and tell whether the second set is more, less, or equal to the first set. Can a child build a second set with one more, one less, or equal to the first set?
Part / Part / Whole: Compose and decompose sets by looking at the whole and the parts that make up the whole.
7 is the “focus number”
1 and 6 are bonds of 7
Unitizing: The child is able to move from counting by ones to count by sets / groups: fives, tens, etc.
This is the Part 3 of Number Talks. If you are just tuning in, please refer to NT Parts 1 and 2. As I mentioned before, conducting a Number Talk session with your students is a chance for them to explain different ways to solve the same problem. This is meant to highlight strategies which have already been taught.
Click below to watch 2 videos of how to conduct a Number Talk session with intermediate students. You will see many strategies being used.
Addition and Subtraction Strategies: I like using the methods listed below before teaching the standard algorithm. This is because they build on a solid knowledge of place value (and number bonds 1-10). If your students are adding and subtracting using the standard algorithm and can’t adequately explain the meaning of the regrouping process in terms of place value, then try one of the following methods. In many cases, I will ask a student the meaning of the “1” that has been “carried” over in double-digit addition. About 85% of the time, the student cannot explain that the “1” represents a group of 10. When adding the tens’ column, they often forget they are adding groups of 10 and not single digits. So they get caught up in the steps and don’t always think about the magnitude of the number (which is part of number sense). You will notice teachers write the problems horizontally in order to elicit the most strategies possible.
Place Value Decomposition
Open Number Line (to add or subtract)
Here are some possible Number Talk problems and solutions:
Notice use of place value and number bonds.
These methds build strong number sense.
I call this “Facts Of.” You can use any number.
Multiplication and Division Strategies: I like using these methods before teaching the standard algorithms. Again, they build a solid understanding of place value, the use of the distributive property, and how knowledge of doubling and halving increases the ability to compute problems mentally. Once these methods have been learned, then it is easy to explain the steps in the standard algorithm.
Doubling and Halving
Here are some possible Number Talk problems and solutions:
Use the known (6 x 2) to learn the unknown problem.
Use the distributive property!
To divide by 4, halve the number twice. To divide by 8, halve the number 3 times.
For 1st -3rd grade students: Refer to “Number Talks Part I” (posted Nov. 12, 2016) for ways to conduct a Number Talk with KG and early 1st grade students (focusing on subitizing and number bonds). For students in 1st – 3rd grade, place extra emphasis on number bonds of 10.
Problem: 8 + 6
Problem: 15 + 9
Problem: 18 – 9
Problem: 35 + 22
Problem: 99 + 6
Problem: 200 – 48
Write a problem on the board, easel, or chart tablet with students sitting nearby to allow for focused discussion. Have the following available for reference and support: ten frame, part-part-whole template, base ten manipulatives, and a 0-100 chart. Present addition and subtraction problems to assist with recall of the following strategies. If time allows, post another similar problem so students can relate previous strategy to new problem. Students show thumbs up when they have an answer in mind. The teacher checks with a few on their answer. Then he/she asks, “How did you solve this problem?” The teacher writes how each student solved the problem.
Reference these videos on youtube.com for examples by clicking on the link:
Number Bonds are pairs of numbers that combine to total the target or focus number. When students learn number bonds they are applying the commutative, identity, and zero properties. PLUS, the information can be applied to both addition and subtraction problems. Number bonds of 10 are very critical to our place value system, and will enhance a student’s success with future addition and subtraction strategies such as use of an open number line.
To build number sense, students need frequent exposure or review of concepts you have previously introduced. There are many ways to build number sense on an on-going, informal basis – especially when you can squeeze in 10-15 minutes daily: