Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 826 · 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. 1.834 − 397 =
2. 2.586 − 127 =
3. 3.793 − 518 =
4. 4.756 − 297 =
5. 5.275 − 168 =
6. 6.901 − 497 =
7. 7.865 − 539 =
8. 8.506 − 398 =
9. 9.748 − 298 =
10. 10.770 − 569 =
11. 11.989 − 627 =
12. 12.331 − 299 =
13. 13.811 − 569 =
14. 14.457 − 299 =
15. 15.948 − 697 =
16. 16.878 − 678 =
17. 17.585 − 567 =
18. 18.644 − 398 =
19. 19.853 − 597 =
20. 20.780 − 499 =
21. 21.858 − 797 =
22. 22.558 − 517 =
23. 23.816 − 498 =
24. 24.394 − 167 =
25. 25.677 − 329 =
26. 26.906 − 199 =
27. 27.618 − 547 =
28. 28.777 − 597 =
29. 29.907 − 697 =
30. 30.643 − 618 =
31. 31.942 − 448 =
32. 32.828 − 298 =
33. 33.695 − 149 =
34. 34.690 − 358 =
35. 35.493 − 457 =
36. 36.412 − 288 =
37. 37.829 − 347 =
38. 38.594 − 577 =
39. 39.591 − 148 =
40. 40.988 − 597 =

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