This document discusses number bonds and strategies for addition and subtraction using number bonds. Number bonds show the different combinations of numbers that make up a given number. They help build foundations for efficiently learning addition and subtraction. The document outlines activities and strategies like near-10, doubles, and near-100 that use number bonds to develop number sense and mental math skills before learning formal algorithms.

1. Whole Numbers
Addition & Subtraction
Marshall Cavendish Institute
Peggy Foo

2. Learning Outcomes
 State the purpose of number bonds
 Use addition and subtraction strategies

3. Number Bonds
 Number bonds are different combinations
of numbers that make up a given number.

4. Different Types of Bonds
67 - 56 = 11
7 – 1 + 5 x 2 = 16
2+3=5
80 ÷ 10 = 8
7 X 8 = 56

5. Purposes
 Number bonds lay a strong foundation for
learning addition and subtraction
efficiently.
 Number bonds also enhance mental
computations

6. Activities for Lower Grades
 Using the magnets and 10-frame
 How many bonds are there to make 10?

7.  Use concrete manipulative
 Generate different possible ways/ bonds
 Move to pictorial stage

9. Extension
 What are the different sums that you can get with
different sets of whole numbers?
 What can you observe?
 What can you observe about the number in the middle?
 What can you observe about the sums?

12.  Open-ended task (with more than 1 sum)
 Generate different possible ways/ bonds
 Problem-solving task

13. Addition Strategies using Number
Bonds
 Near-10 Strategy
1
2
1
3
3

15.  The Doubles Strategy
1
2
1
3
3

16. Addition Strategies using Number
Bonds
 Near-100 Strategy
 245 + 98

17. Addition Strategies using Number
Bonds
 Near-100 Strategy
 245 + 98
Rewrite 98 as (100-2)
Add 245 + 100 = 345
We add more than we should
345 – 2 = 343

18. Debriefing
 The ability to see numbers in different
combinations is developing number
sense/ number concept.

19. How many ways to find the value of
 43 + 29

20. Additional Strategies using Number
Bonds
 Using Hundred Chart
 43 + 29 = 43 + 30-1 (near-ten strategy)
= 73-1
= 72
 43 + 29 = 60 + 12 (place value concept)
= 72

21. Subtraction Strategies using
Number Bonds
 Addition bonds for Subtraction
16 – 9

22. Subtraction Strategies using
Number Bonds
 Addition bonds for Subtraction
16 – 9
16 is made up of (10 + 6)
Use 10 – 9 = 1
Add 1 to 6 (remaining number in the bond)
1+6=7

23. Subtraction Strategies using
Number Bonds
 Near-100 Subtraction Strategy
256 - 97

24. Subtraction Strategies using
Number Bonds
 Near-100 Subtraction Strategy
256 - 97
Rewrite 97 as (100 – 3)
256 – 100 = 156
Subtract more than we should
156 + 3 = 159

25. How many ways to find the
value of
 67- 49

26. Subtraction (renaming once)
 67-49 = 67-50 +1 (near 10 strategy)
= 17+1
= 18
 67-49 = 18 (place value concept)

27. Place Value Concept
 To add and subtract using formal
algorithms
 Use place value concept to develop
conceptual understanding
 Use base ten

28. Summary
 Concrete-Pictorial-Abstract Approach
 Aim to develop conceptual understanding
before procedural understanding (Richard
Skemp)

29. Summary
Mental Strategies Formal Algorithm
involving number bonds
Addition Strategies: Place value concept
1) Near-10 Strategy
2) The doubles Strategy
3) Near-100 Strategy
Subtraction Strategies:
1) Addition Bonds for
subtraction
2) Near-100 Subtraction
Strategy