Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 227 · 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. 1.851 − 498 =
2. 2.732 − 677 =
3. 3.942 − 207 =
4. 4.863 − 599 =
5. 5.734 − 327 =
6. 6.979 − 389 =
7. 7.964 − 607 =
8. 8.968 − 448 =
9. 9.984 − 499 =
10. 10.780 − 499 =
11. 11.690 − 649 =
12. 12.834 − 139 =
13. 13.538 − 509 =
14. 14.451 − 397 =
15. 15.548 − 399 =
16. 16.507 − 219 =
17. 17.950 − 598 =
18. 18.783 − 599 =
19. 19.569 − 538 =
20. 20.817 − 449 =
21. 21.587 − 467 =
22. 22.904 − 159 =
23. 23.489 − 198 =
24. 24.841 − 217 =
25. 25.713 − 197 =
26. 26.760 − 278 =
27. 27.787 − 467 =
28. 28.971 − 257 =
29. 29.444 − 229 =
30. 30.873 − 388 =
31. 31.607 − 477 =
32. 32.990 − 597 =
33. 33.507 − 428 =
34. 34.366 − 159 =
35. 35.807 − 429 =
36. 36.557 − 199 =
37. 37.829 − 599 =
38. 38.975 − 799 =
39. 39.253 − 199 =
40. 40.960 − 688 =

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