### Key Concepts:

- Understanding the Addition properties
- Associative property
- Commutative property
- Additive identity
- Addition table
- Pattern in addition table
- Shapes in addition table

**8.2.1 Introduction to addition table: **

### Addition Table Chart

The addition table chart for the numbers 1 to 10 can be represented as shown in the figure below.

### Pattern:

Number pattern is a pattern or sequence in a series of numbers. This pattern generally establishes a common relationship between all numbers. For example: 0, 5, 10, 15, 20, 25, …

### 8.2.2 Addition pattern:

Associative property:

20 + 24 = 20 + (2 +22)

= (20 + 2) + 22

** **20 + 24 = 22 + 22

Commutative property:

20 + 24 = (16 + 4) + (18 + 6)

22 + 22 = (18 + 4) + (16 + 6)

The alternating odd and even numbers in the rows and columns are captured in the following picture:

The reason for the alternating pattern is that each time we move to the box on the right or one below, we are adding one more to our sum. For example,

(2 + 3) +1 = 2 + (3 + 1) = 2+4

### Commutative Property.

Add the diagonals to any box.

2 + 4 = 6

3 + 3 = 6

Are the sums of the diagonals always equal?

6 + 8 + 10 = 24

8 + 8 + 8 = 24

6 is 2 less than 8; 10 is 2 more than 8.

## Exercise:

- Write addition table for 4.
- Write addition table for 6.
- Complete the addition chart

4. Find the next numbers

5. What numbers are missing?

33, ____, 53, _____, 73, 83, 93, _____

6. Identify the numbers by which the following series of numbers are skipping the counting?

123, 125, 127, 129, 131, 133, 135, 137

7. Use a number line to evaluate each of the following

8. The following problem is an example of which property?

(3+1)+2=3+(1+2)

9. What number fills in the blank?

i) 5 + ____ = 8 + 5

ii) 8 + 4 = ______ + 8

10. Complete the addition

i) 79 + 1 = ______

ii) 173 + ______ = 174

iii) ______ + 1 = 1460

### What we have learned:

- Understanding the Addition properties
- Associative property
- Commutative property
- Additive identity
- Addition table
- Pattern in addition table
- Shapes in addition table

## Concept Map:

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