Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 953 · 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. 1.519 − 199 =
2. 2.875 − 127 =
3. 3.609 − 239 =
4. 4.591 − 399 =
5. 5.682 − 598 =
6. 6.506 − 217 =
7. 7.481 − 168 =
8. 8.991 − 359 =
9. 9.340 − 299 =
10. 10.825 − 698 =
11. 11.926 − 497 =
12. 12.165 − 139 =
13. 13.425 − 408 =
14. 14.493 − 168 =
15. 15.273 − 197 =
16. 16.747 − 377 =
17. 17.741 − 689 =
18. 18.596 − 499 =
19. 19.747 − 597 =
20. 20.657 − 497 =
21. 21.504 − 398 =
22. 22.720 − 499 =
23. 23.546 − 288 =
24. 24.860 − 699 =
25. 25.824 − 158 =
26. 26.463 − 399 =
27. 27.548 − 148 =
28. 28.438 − 187 =
29. 29.633 − 448 =
30. 30.740 − 498 =
31. 31.267 − 217 =
32. 32.477 − 429 =
33. 33.293 − 248 =
34. 34.510 − 249 =
35. 35.710 − 219 =
36. 36.940 − 439 =
37. 37.815 − 799 =
38. 38.970 − 798 =
39. 39.734 − 599 =
40. 40.940 − 597 =

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