Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 360 · 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. 1.788 − 699 =
2. 2.549 − 528 =
3. 3.751 − 699 =
4. 4.728 − 598 =
5. 5.996 − 338 =
6. 6.463 − 399 =
7. 7.565 − 298 =
8. 8.983 − 598 =
9. 9.651 − 488 =
10. 10.283 − 197 =
11. 11.947 − 279 =
12. 12.607 − 397 =
13. 13.877 − 798 =
14. 14.966 − 557 =
15. 15.721 − 599 =
16. 16.416 − 367 =
17. 17.927 − 679 =
18. 18.403 − 197 =
19. 19.852 − 797 =
20. 20.848 − 598 =
21. 21.576 − 168 =
22. 22.958 − 698 =
23. 23.698 − 678 =
24. 24.764 − 598 =
25. 25.418 − 198 =
26. 26.607 − 499 =
27. 27.744 − 397 =
28. 28.802 − 557 =
29. 29.538 − 357 =
30. 30.985 − 689 =
31. 31.524 − 389 =
32. 32.498 − 297 =
33. 33.898 − 599 =
34. 34.748 − 678 =
35. 35.595 − 287 =
36. 36.933 − 647 =
37. 37.668 − 499 =
38. 38.251 − 158 =
39. 39.560 − 398 =
40. 40.677 − 579 =

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