operations · Year 1 · AC9M1N04
Subtraction within twenty
Take away in two steps. First take away the ones to reach ten, then take away what is still left. To subtract 6 from 14, take away 4 to reach 10, then take away the other 2 to reach 8. For a missing number, add the jump down to ten and the jump from ten.
Sample questions
16 − 7 = ?
- Split 7 into 6 and 1.
- Take 6 to reach ten: 16 − 6 = 10.
- Take the other 1: 10 − 1 = 9.
- So 16 − 7 = 9.
Answer: 9
11 − 2 = ?
- Split 2 into 1 and 1.
- Take 1 to reach ten: 11 − 1 = 10.
- Take the other 1: 10 − 1 = 9.
- So 11 − 2 = 9.
Answer: 9
13 − 4 = ?
- Split 4 into 3 and 1.
- Take 3 to reach ten: 13 − 3 = 10.
- Take the other 1: 10 − 1 = 9.
- So 13 − 4 = 9.
Answer: 9