Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 323 · 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. 1.541 − 297 =
2. 2.550 − 269 =
3. 3.784 − 588 =
4. 4.596 − 327 =
5. 5.219 − 197 =
6. 6.654 − 598 =
7. 7.779 − 229 =
8. 8.275 − 199 =
9. 9.934 − 299 =
10. 10.815 − 399 =
11. 11.698 − 597 =
12. 12.788 − 219 =
13. 13.550 − 399 =
14. 14.582 − 468 =
15. 15.851 − 197 =
16. 16.546 − 399 =
17. 17.818 − 279 =
18. 18.909 − 299 =
19. 19.868 − 697 =
20. 20.799 − 499 =
21. 21.587 − 409 =
22. 22.522 − 467 =
23. 23.968 − 698 =
24. 24.380 − 307 =
25. 25.737 − 467 =
26. 26.641 − 498 =
27. 27.894 − 568 =
28. 28.702 − 299 =
29. 29.960 − 657 =
30. 30.794 − 129 =
31. 31.853 − 439 =
32. 32.835 − 597 =
33. 33.661 − 358 =
34. 34.769 − 199 =
35. 35.863 − 799 =
36. 36.444 − 429 =
37. 37.306 − 238 =
38. 38.819 − 797 =
39. 39.503 − 409 =
40. 40.920 − 399 =

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