Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 502 · 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. 1.838 − 127 =
2. 2.955 − 399 =
3. 3.902 − 298 =
4. 4.611 − 497 =
5. 5.667 − 527 =
6. 6.642 − 628 =
7. 7.708 − 499 =
8. 8.847 − 799 =
9. 9.909 − 657 =
10. 10.917 − 157 =
11. 11.497 − 397 =
12. 12.671 − 598 =
13. 13.836 − 598 =
14. 14.442 − 398 =
15. 15.540 − 298 =
16. 16.555 − 407 =
17. 17.682 − 589 =
18. 18.483 − 247 =
19. 19.897 − 399 =
20. 20.851 − 798 =
21. 21.619 − 517 =
22. 22.927 − 299 =
23. 23.773 − 699 =
24. 24.583 − 217 =
25. 25.378 − 297 =
26. 26.799 − 548 =
27. 27.775 − 587 =
28. 28.342 − 207 =
29. 29.585 − 498 =
30. 30.508 − 209 =
31. 31.925 − 617 =
32. 32.576 − 558 =
33. 33.914 − 487 =
34. 34.833 − 797 =
35. 35.861 − 797 =
36. 36.914 − 699 =
37. 37.528 − 298 =
38. 38.759 − 557 =
39. 39.510 − 298 =
40. 40.729 − 399 =

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