Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 433 · 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. 1.854 − 498 =
2. 2.885 − 397 =
3. 3.438 − 398 =
4. 4.917 − 667 =
5. 5.405 − 389 =
6. 6.286 − 217 =
7. 7.779 − 237 =
8. 8.650 − 398 =
9. 9.547 − 508 =
10. 10.931 − 609 =
11. 11.577 − 388 =
12. 12.713 − 567 =
13. 13.951 − 647 =
14. 14.772 − 539 =
15. 15.425 − 139 =
16. 16.808 − 287 =
17. 17.433 − 208 =
18. 18.394 − 299 =
19. 19.957 − 798 =
20. 20.990 − 299 =
21. 21.612 − 598 =
22. 22.887 − 197 =
23. 23.825 − 199 =
24. 24.872 − 589 =
25. 25.728 − 299 =
26. 26.720 − 427 =
27. 27.951 − 307 =
28. 28.560 − 117 =
29. 29.818 − 298 =
30. 30.273 − 199 =
31. 31.473 − 129 =
32. 32.736 − 598 =
33. 33.989 − 417 =
34. 34.989 − 398 =
35. 35.718 − 219 =
36. 36.816 − 697 =
37. 37.631 − 379 =
38. 38.830 − 799 =
39. 39.646 − 118 =
40. 40.974 − 317 =

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