Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 488 · 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. 1.947 − 799 =
2. 2.336 − 198 =
3. 3.981 − 598 =
4. 4.769 − 198 =
5. 5.913 − 699 =
6. 6.601 − 489 =
7. 7.612 − 597 =
8. 8.442 − 357 =
9. 9.926 − 599 =
10. 10.909 − 297 =
11. 11.557 − 297 =
12. 12.863 − 699 =
13. 13.695 − 199 =
14. 14.843 − 197 =
15. 15.723 − 199 =
16. 16.957 − 599 =
17. 17.626 − 399 =
18. 18.667 − 598 =
19. 19.350 − 118 =
20. 20.955 − 509 =
21. 21.491 − 367 =
22. 22.614 − 418 =
23. 23.826 − 667 =
24. 24.664 − 197 =
25. 25.838 − 598 =
26. 26.953 − 697 =
27. 27.864 − 448 =
28. 28.823 − 119 =
29. 29.509 − 259 =
30. 30.911 − 657 =
31. 31.793 − 397 =
32. 32.584 − 559 =
33. 33.717 − 127 =
34. 34.508 − 299 =
35. 35.843 − 598 =
36. 36.911 − 199 =
37. 37.399 − 298 =
38. 38.991 − 797 =
39. 39.822 − 297 =
40. 40.740 − 699 =

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