In this worksheet, you must know your subtracting number bonds up to 20.
And that means knowing them off by heart.
Example
18 - 3
Answer
15
Remember
14 - 10 = 4 and 17 - 10 = 7 and so on.
16 - 6 = 10 and 18 - 8 = 10 and so on.
5 - 0 = 5 and 19 - 0 = 19 and so on.
8 - 8 = 0 and 12 - 12 = 0 and so on.