addition within 20

• Building up number bonds• Use the addition symbol (+) to write

a mathematical sentence• Solving 1-step word problems involving addition

What will we learn today?

Whole Numbers

Addition Within 20

Number Bonds

whole

part

part

part + part = whole

We use this symbol to do addition.

2 and 3 make 5

2 + 3 = 5

There are 5 cars altogether.

5

2

3

Here’s an example.

10

?

?

To make 10, we can have a

few combination of

numbers.

1 and 9 make 10

2 and 8 make 10

3 and 7 make 10

4 and 6 make 10

5 and 5 make 10

Here’s another example.

8

?

6

whole = 81 part = 6

6 and 2 make 8.

Here’s another example.

By using the count-on method, you can easily add to find the answer.

+1+1+1

6 7 8

5 + 3 = 8

11

11 + 3 = 14

12

13

14

Here’s another example.

More than

4 more than 6 is __________.

4 + 6 = 10

5 more than 8 is __________.

5 + 8 = 13

Word Problem

Jane has 9 sweets. Her sister gives her 3 more sweets. How many sweets does Jane have now?

9 + 3 = 12

She has 12 sweets now.

Here’s another example.

Tommy bought 10 marbles. Ali bought 6 marbles. How many marbles did they have altogether?

10 + 6 = 16

They had 16 marbles altogether.

Are you ready to try out the questions?