Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 557 · 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. 1.661 − 199 =
2. 2.624 − 458 =
3. 3.834 − 797 =
4. 4.588 − 498 =
5. 5.662 − 137 =
6. 6.526 − 218 =
7. 7.696 − 299 =
8. 8.851 − 697 =
9. 9.773 − 677 =
10. 10.990 − 537 =
11. 11.679 − 589 =
12. 12.715 − 469 =
13. 13.487 − 387 =
14. 14.954 − 568 =
15. 15.700 − 147 =
16. 16.982 − 648 =
17. 17.899 − 697 =
18. 18.682 − 368 =
19. 19.802 − 519 =
20. 20.896 − 679 =
21. 21.762 − 417 =
22. 22.950 − 609 =
23. 23.607 − 299 =
24. 24.361 − 149 =
25. 25.713 − 617 =
26. 26.189 − 128 =
27. 27.432 − 199 =
28. 28.353 − 127 =
29. 29.908 − 798 =
30. 30.769 − 598 =
31. 31.675 − 608 =
32. 32.726 − 298 =
33. 33.223 − 189 =
34. 34.826 − 519 =
35. 35.870 − 797 =
36. 36.818 − 388 =
37. 37.950 − 499 =
38. 38.805 − 658 =
39. 39.594 − 448 =
40. 40.321 − 239 =

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