Grades 1–3
Subtraction
Subtraction finds what is left, or the difference between two numbers. Every subtraction can be checked with an addition.
Work it out.
Ten questions at a time, marked as you go. Pick a skill above and start; nothing to sign up for, and the set works offline once the page has loaded.
What subtraction means
Taking 4 away from 9 leaves 5. The same sum also answers "how far is it from 4 to 9?", which is why counting up is a real method and not a trick.
Unlike addition, order matters: 9 − 4 is not the same as 4 − 9. To check an answer, add it back: if 52 − 17 = 35, then 35 + 17 should be 52.
Worked examples
Column subtraction
Every top digit is big enough, so each column is taken on its own.
Exchanging a ten
2 − 8 can't be done, so one ten becomes ten ones: 12 − 8 = 4, then 4 − 2 = 2 and 3 − 1 = 2.
Across zeros
There are no tens to take from, so a hundred becomes 9 tens and 10 ones.
Strategies that help
Count up
82 − 77: from 77 it is 3 to 80, then 2 more to 82. The difference is 5.
Tens, then ones
74 − 38: take 30 to get 44, then 8 more to get 36.
Round and adjust
63 − 19: take 20 to get 43, then give back the extra 1. The answer is 44.
Check with addition
Add the answer to the number taken away. You should get back where you started.
Fact families
Three numbers give four facts. Learning them together means every addition fact also teaches two subtractions.
| Add | Add | Subtract | Subtract |
|---|---|---|---|
| 3 + 5 = 8 | 5 + 3 = 8 | 8 − 3 = 5 | 8 − 5 = 3 |
| 4 + 7 = 11 | 7 + 4 = 11 | 11 − 4 = 7 | 11 − 7 = 4 |
| 6 + 9 = 15 | 9 + 6 = 15 | 15 − 6 = 9 | 15 − 9 = 6 |
| 7 + 8 = 15 | 8 + 7 = 15 | 15 − 7 = 8 | 15 − 8 = 7 |
Practice questions
Work each one on paper first, then open the answer to check it.
- 15 − 8
Answer
7 - 13 − 6
Answer
7 - 68 − 25
Answer
43 - 72 − 39
Answer
33 - 547 − 312
Answer
235 - 634 − 258
Answer
376 - 500 − 147
Answer
353 - 1,000 − 365
Answer
635 - A book has 120 pages. Maya has read 85. How many pages are left?
Answer
35 - What is the difference between 91 and 56?
Answer
35
Common questions
- Why not just take the smaller digit from the bigger one in each column?
- Because it gives the wrong answer. For 52 − 17 it would give 45, but the answer is 35. When the top digit is smaller, exchange a ten from the next column instead.
- Borrowing, exchanging, regrouping: are they different?
- No. All three name the same step: one unit of the next column is broken into ten of this one.