Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 754 · 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. 1.944 − 698 =
2. 2.465 − 289 =
3. 3.580 − 398 =
4. 4.961 − 538 =
5. 5.850 − 799 =
6. 6.953 − 698 =
7. 7.608 − 589 =
8. 8.614 − 598 =
9. 9.715 − 598 =
10. 10.605 − 437 =
11. 11.520 − 409 =
12. 12.934 − 499 =
13. 13.512 − 199 =
14. 14.759 − 699 =
15. 15.408 − 257 =
16. 16.505 − 299 =
17. 17.711 − 298 =
18. 18.706 − 599 =
19. 19.297 − 209 =
20. 20.687 − 599 =
21. 21.714 − 549 =
22. 22.335 − 298 =
23. 23.588 − 499 =
24. 24.517 − 199 =
25. 25.956 − 327 =
26. 26.719 − 599 =
27. 27.964 − 698 =
28. 28.773 − 699 =
29. 29.872 − 607 =
30. 30.366 − 298 =
31. 31.313 − 198 =
32. 32.468 − 298 =
33. 33.869 − 298 =
34. 34.941 − 597 =
35. 35.580 − 198 =
36. 36.985 − 597 =
37. 37.572 − 268 =
38. 38.798 − 637 =
39. 39.693 − 399 =
40. 40.673 − 597 =

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