Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 986 · 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. 1.713 − 498 =
2. 2.617 − 198 =
3. 3.549 − 438 =
4. 4.850 − 497 =
5. 5.999 − 649 =
6. 6.840 − 299 =
7. 7.654 − 559 =
8. 8.577 − 308 =
9. 9.898 − 397 =
10. 10.565 − 498 =
11. 11.939 − 458 =
12. 12.733 − 599 =
13. 13.599 − 519 =
14. 14.753 − 268 =
15. 15.825 − 397 =
16. 16.415 − 398 =
17. 17.715 − 698 =
18. 18.747 − 458 =
19. 19.620 − 399 =
20. 20.771 − 359 =
21. 21.921 − 198 =
22. 22.917 − 797 =
23. 23.687 − 587 =
24. 24.630 − 398 =
25. 25.232 − 209 =
26. 26.851 − 598 =
27. 27.540 − 297 =
28. 28.758 − 598 =
29. 29.557 − 499 =
30. 30.996 − 647 =
31. 31.410 − 307 =
32. 32.313 − 198 =
33. 33.972 − 538 =
34. 34.726 − 399 =
35. 35.959 − 298 =
36. 36.831 − 308 =
37. 37.496 − 197 =
38. 38.543 − 197 =
39. 39.984 − 798 =
40. 40.250 − 198 =

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