Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 909 · 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. 1.384 − 328 =
2. 2.976 − 299 =
3. 3.770 − 499 =
4. 4.922 − 299 =
5. 5.788 − 299 =
6. 6.647 − 498 =
7. 7.933 − 687 =
8. 8.899 − 398 =
9. 9.695 − 369 =
10. 10.347 − 197 =
11. 11.958 − 799 =
12. 12.959 − 557 =
13. 13.946 − 619 =
14. 14.381 − 207 =
15. 15.471 − 197 =
16. 16.766 − 598 =
17. 17.888 − 678 =
18. 18.644 − 597 =
19. 19.879 − 797 =
20. 20.588 − 147 =
21. 21.883 − 148 =
22. 22.620 − 398 =
23. 23.731 − 549 =
24. 24.952 − 498 =
25. 25.738 − 477 =
26. 26.810 − 297 =
27. 27.962 − 617 =
28. 28.882 − 497 =
29. 29.643 − 298 =
30. 30.752 − 397 =
31. 31.802 − 278 =
32. 32.681 − 598 =
33. 33.489 − 258 =
34. 34.961 − 599 =
35. 35.643 − 498 =
36. 36.324 − 297 =
37. 37.546 − 297 =
38. 38.786 − 289 =
39. 39.864 − 798 =
40. 40.782 − 368 =

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