Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 60 · 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. 1.875 − 287 =
2. 2.766 − 697 =
3. 3.645 − 299 =
4. 4.658 − 599 =
5. 5.864 − 309 =
6. 6.649 − 178 =
7. 7.291 − 199 =
8. 8.865 − 197 =
9. 9.226 − 197 =
10. 10.433 − 198 =
11. 11.759 − 498 =
12. 12.387 − 247 =
13. 13.682 − 399 =
14. 14.851 − 297 =
15. 15.953 − 679 =
16. 16.957 − 499 =
17. 17.940 − 397 =
18. 18.902 − 598 =
19. 19.724 − 197 =
20. 20.890 − 468 =
21. 21.554 − 288 =
22. 22.489 − 399 =
23. 23.838 − 237 =
24. 24.833 − 799 =
25. 25.485 − 119 =
26. 26.619 − 328 =
27. 27.665 − 298 =
28. 28.438 − 297 =
29. 29.836 − 799 =
30. 30.656 − 467 =
31. 31.460 − 259 =
32. 32.710 − 198 =
33. 33.434 − 338 =
34. 34.881 − 197 =
35. 35.834 − 669 =
36. 36.907 − 488 =
37. 37.793 − 699 =
38. 38.926 − 488 =
39. 39.968 − 608 =
40. 40.942 − 599 =

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