Add missing elements to make a statement true with totals up to 20

We use number sentences to represent problems in mathematics. Watch this video to see how.

When you see the equal sign it means both sides have to balance. A number sentence is like a set of scales. To keep it balanced, both sides need to equal the same number. Look at the picture below. We can see there are 5 blocks on one side and 5 blocks on the other, so it is balanced.

When the two sides of the number sentence are equal we say the statement is true.

Example: Fill in the missing number to make the number sentence true.    

                       $4+2=3+\editable{}$4+2=3+

The missing number must be $3$3.

Worked Examples: