Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 160 · 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. 1.262 − 198 =
2. 2.517 − 497 =
3. 3.919 − 698 =
4. 4.559 − 308 =
5. 5.499 − 299 =
6. 6.423 − 197 =
7. 7.687 − 199 =
8. 8.916 − 799 =
9. 9.664 − 599 =
10. 10.556 − 398 =
11. 11.572 − 398 =
12. 12.419 − 328 =
13. 13.693 − 398 =
14. 14.864 − 377 =
15. 15.679 − 587 =
16. 16.718 − 697 =
17. 17.870 − 198 =
18. 18.515 − 299 =
19. 19.323 − 179 =
20. 20.687 − 298 =
21. 21.633 − 599 =
22. 22.263 − 149 =
23. 23.978 − 598 =
24. 24.576 − 199 =
25. 25.994 − 699 =
26. 26.995 − 638 =
27. 27.713 − 669 =
28. 28.916 − 598 =
29. 29.620 − 308 =
30. 30.489 − 298 =
31. 31.523 − 317 =
32. 32.439 − 119 =
33. 33.561 − 399 =
34. 34.777 − 627 =
35. 35.866 − 498 =
36. 36.444 − 427 =
37. 37.935 − 669 =
38. 38.430 − 299 =
39. 39.500 − 297 =
40. 40.834 − 698 =

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