Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 340 · 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. 1.693 − 198 =
2. 2.853 − 799 =
3. 3.623 − 298 =
4. 4.690 − 499 =
5. 5.674 − 197 =
6. 6.867 − 299 =
7. 7.756 − 698 =
8. 8.322 − 197 =
9. 9.736 − 618 =
10. 10.957 − 597 =
11. 11.666 − 437 =
12. 12.982 − 199 =
13. 13.674 − 297 =
14. 14.452 − 397 =
15. 15.651 − 598 =
16. 16.354 − 299 =
17. 17.659 − 518 =
18. 18.501 − 339 =
19. 19.515 − 299 =
20. 20.423 − 397 =
21. 21.588 − 119 =
22. 22.923 − 497 =
23. 23.874 − 597 =
24. 24.933 − 499 =
25. 25.969 − 537 =
26. 26.951 − 547 =
27. 27.778 − 698 =
28. 28.833 − 698 =
29. 29.761 − 688 =
30. 30.972 − 599 =
31. 31.687 − 298 =
32. 32.346 − 199 =
33. 33.447 − 208 =
34. 34.718 − 497 =
35. 35.899 − 448 =
36. 36.918 − 499 =
37. 37.664 − 247 =
38. 38.778 − 699 =
39. 39.826 − 799 =
40. 40.814 − 799 =

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