Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 264 · 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. 1.850 − 177 =
2. 2.646 − 597 =
3. 3.433 − 359 =
4. 4.423 − 297 =
5. 5.356 − 197 =
6. 6.852 − 508 =
7. 7.955 − 348 =
8. 8.471 − 429 =
9. 9.987 − 127 =
10. 10.819 − 699 =
11. 11.382 − 309 =
12. 12.489 − 397 =
13. 13.813 − 189 =
14. 14.958 − 599 =
15. 15.940 − 799 =
16. 16.592 − 488 =
17. 17.937 − 647 =
18. 18.747 − 649 =
19. 19.626 − 359 =
20. 20.789 − 199 =
21. 21.945 − 598 =
22. 22.943 − 507 =
23. 23.648 − 628 =
24. 24.812 − 479 =
25. 25.821 − 797 =
26. 26.495 − 198 =
27. 27.986 − 799 =
28. 28.767 − 597 =
29. 29.995 − 798 =
30. 30.453 − 398 =
31. 31.979 − 799 =
32. 32.842 − 497 =
33. 33.496 − 477 =
34. 34.199 − 159 =
35. 35.636 − 499 =
36. 36.415 − 198 =
37. 37.585 − 497 =
38. 38.931 − 799 =
39. 39.748 − 578 =
40. 40.502 − 199 =

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