Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 166 · 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. 1.979 − 297 =
2. 2.850 − 697 =
3. 3.620 − 497 =
4. 4.636 − 599 =
5. 5.782 − 629 =
6. 6.767 − 147 =
7. 7.474 − 138 =
8. 8.564 − 519 =
9. 9.935 − 798 =
10. 10.664 − 597 =
11. 11.749 − 699 =
12. 12.573 − 499 =
13. 13.698 − 598 =
14. 14.760 − 609 =
15. 15.439 − 209 =
16. 16.855 − 199 =
17. 17.371 − 297 =
18. 18.850 − 359 =
19. 19.596 − 258 =
20. 20.744 − 699 =
21. 21.689 − 518 =
22. 22.739 − 699 =
23. 23.914 − 538 =
24. 24.938 − 798 =
25. 25.530 − 468 =
26. 26.972 − 657 =
27. 27.724 − 699 =
28. 28.941 − 667 =
29. 29.482 − 169 =
30. 30.566 − 419 =
31. 31.897 − 558 =
32. 32.611 − 579 =
33. 33.824 − 397 =
34. 34.599 − 399 =
35. 35.531 − 407 =
36. 36.487 − 279 =
37. 37.269 − 159 =
38. 38.802 − 299 =
39. 39.727 − 399 =
40. 40.668 − 287 =

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