Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 94 · 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. 1.625 − 598 =
2. 2.463 − 158 =
3. 3.709 − 658 =
4. 4.913 − 799 =
5. 5.983 − 799 =
6. 6.150 − 119 =
7. 7.657 − 299 =
8. 8.652 − 287 =
9. 9.694 − 408 =
10. 10.859 − 688 =
11. 11.554 − 479 =
12. 12.951 − 499 =
13. 13.663 − 399 =
14. 14.430 − 178 =
15. 15.740 − 599 =
16. 16.434 − 307 =
17. 17.479 − 458 =
18. 18.347 − 299 =
19. 19.745 − 689 =
20. 20.790 − 337 =
21. 21.612 − 479 =
22. 22.836 − 289 =
23. 23.720 − 199 =
24. 24.684 − 238 =
25. 25.626 − 528 =
26. 26.540 − 357 =
27. 27.690 − 237 =
28. 28.738 − 527 =
29. 29.860 − 698 =
30. 30.793 − 498 =
31. 31.827 − 429 =
32. 32.669 − 527 =
33. 33.571 − 399 =
34. 34.841 − 398 =
35. 35.715 − 548 =
36. 36.384 − 297 =
37. 37.720 − 167 =
38. 38.806 − 698 =
39. 39.657 − 497 =
40. 40.378 − 348 =

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