Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 99 · 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. 1.882 − 539 =
2. 2.662 − 498 =
3. 3.714 − 119 =
4. 4.472 − 199 =
5. 5.914 − 198 =
6. 6.799 − 549 =
7. 7.961 − 298 =
8. 8.928 − 597 =
9. 9.391 − 169 =
10. 10.639 − 198 =
11. 11.818 − 258 =
12. 12.907 − 798 =
13. 13.540 − 399 =
14. 14.850 − 679 =
15. 15.247 − 197 =
16. 16.937 − 438 =
17. 17.715 − 477 =
18. 18.961 − 699 =
19. 19.603 − 508 =
20. 20.655 − 217 =
21. 21.917 − 169 =
22. 22.449 − 387 =
23. 23.513 − 298 =
24. 24.933 − 399 =
25. 25.896 − 799 =
26. 26.847 − 698 =
27. 27.711 − 498 =
28. 28.623 − 397 =
29. 29.833 − 499 =
30. 30.948 − 257 =
31. 31.555 − 198 =
32. 32.802 − 699 =
33. 33.963 − 589 =
34. 34.920 − 408 =
35. 35.865 − 799 =
36. 36.976 − 449 =
37. 37.759 − 559 =
38. 38.655 − 399 =
39. 39.940 − 568 =
40. 40.631 − 288 =

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