Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 89 · 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. 1.726 − 659 =
2. 2.828 − 597 =
3. 3.459 − 167 =
4. 4.944 − 798 =
5. 5.873 − 797 =
6. 6.650 − 417 =
7. 7.989 − 798 =
8. 8.673 − 298 =
9. 9.943 − 797 =
10. 10.484 − 467 =
11. 11.945 − 219 =
12. 12.642 − 298 =
13. 13.817 − 597 =
14. 14.663 − 497 =
15. 15.528 − 298 =
16. 16.959 − 639 =
17. 17.508 − 298 =
18. 18.945 − 589 =
19. 19.847 − 798 =
20. 20.710 − 398 =
21. 21.731 − 479 =
22. 22.433 − 299 =
23. 23.835 − 298 =
24. 24.695 − 597 =
25. 25.489 − 338 =
26. 26.571 − 499 =
27. 27.569 − 499 =
28. 28.740 − 598 =
29. 29.712 − 598 =
30. 30.940 − 167 =
31. 31.811 − 699 =
32. 32.795 − 398 =
33. 33.970 − 498 =
34. 34.670 − 459 =
35. 35.795 − 559 =
36. 36.630 − 397 =
37. 37.733 − 499 =
38. 38.895 − 798 =
39. 39.641 − 298 =
40. 40.605 − 499 =

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