Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 176 · 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. 1.661 − 288 =
2. 2.660 − 527 =
3. 3.824 − 798 =
4. 4.808 − 597 =
5. 5.704 − 299 =
6. 6.896 − 197 =
7. 7.867 − 299 =
8. 8.891 − 189 =
9. 9.704 − 549 =
10. 10.822 − 297 =
11. 11.907 − 799 =
12. 12.534 − 198 =
13. 13.552 − 339 =
14. 14.989 − 617 =
15. 15.856 − 799 =
16. 16.550 − 197 =
17. 17.918 − 198 =
18. 18.868 − 699 =
19. 19.985 − 399 =
20. 20.776 − 499 =
21. 21.895 − 799 =
22. 22.973 − 297 =
23. 23.530 − 458 =
24. 24.541 − 229 =
25. 25.731 − 699 =
26. 26.663 − 399 =
27. 27.760 − 598 =
28. 28.944 − 588 =
29. 29.719 − 697 =
30. 30.636 − 597 =
31. 31.525 − 137 =
32. 32.968 − 428 =
33. 33.661 − 219 =
34. 34.396 − 198 =
35. 35.732 − 588 =
36. 36.824 − 497 =
37. 37.714 − 637 =
38. 38.902 − 309 =
39. 39.726 − 598 =
40. 40.534 − 397 =

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