Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 11 · 40 questions

How to do it in your head (Round up, add back): Round the number you take away up to the next ten or hundred: 297 → 300 (3 too many). Take away the round number. Add back the extra, because you took away too much.

1. 1.564 − 217 =
2. 2.714 − 299 =
3. 3.607 − 437 =
4. 4.585 − 497 =
5. 5.435 − 398 =
6. 6.543 − 237 =
7. 7.634 − 587 =
8. 8.837 − 798 =
9. 9.376 − 299 =
10. 10.631 − 299 =
11. 11.984 − 698 =
12. 12.725 − 398 =
13. 13.500 − 299 =
14. 14.837 − 229 =
15. 15.745 − 509 =
16. 16.671 − 597 =
17. 17.423 − 267 =
18. 18.871 − 798 =
19. 19.830 − 267 =
20. 20.804 − 398 =
21. 21.486 − 467 =
22. 22.941 − 147 =
23. 23.441 − 357 =
24. 24.630 − 299 =
25. 25.805 − 597 =
26. 26.639 − 298 =
27. 27.843 − 799 =
28. 28.630 − 599 =
29. 29.851 − 498 =
30. 30.544 − 197 =
31. 31.566 − 238 =
32. 32.955 − 198 =
33. 33.279 − 199 =
34. 34.982 − 598 =
35. 35.662 − 297 =
36. 36.718 − 617 =
37. 37.576 − 359 =
38. 38.912 − 799 =
39. 39.383 − 147 =
40. 40.883 − 337 =

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