Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 608 · 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. 1.966 − 597 =
2. 2.380 − 359 =
3. 3.940 − 798 =
4. 4.876 − 599 =
5. 5.540 − 449 =
6. 6.384 − 117 =
7. 7.974 − 577 =
8. 8.625 − 399 =
9. 9.553 − 497 =
10. 10.984 − 497 =
11. 11.867 − 347 =
12. 12.506 − 199 =
13. 13.785 − 519 =
14. 14.760 − 579 =
15. 15.879 − 399 =
16. 16.604 − 497 =
17. 17.921 − 699 =
18. 18.680 − 618 =
19. 19.416 − 299 =
20. 20.675 − 197 =
21. 21.896 − 798 =
22. 22.835 − 499 =
23. 23.642 − 499 =
24. 24.619 − 239 =
25. 25.916 − 599 =
26. 26.815 − 599 =
27. 27.468 − 289 =
28. 28.588 − 439 =
29. 29.414 − 118 =
30. 30.759 − 467 =
31. 31.930 − 799 =
32. 32.674 − 389 =
33. 33.814 − 138 =
34. 34.399 − 197 =
35. 35.889 − 617 =
36. 36.643 − 599 =
37. 37.926 − 649 =
38. 38.735 − 499 =
39. 39.658 − 359 =
40. 40.977 − 239 =

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