Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 569 · 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. 1.474 − 378 =
2. 2.605 − 299 =
3. 3.969 − 799 =
4. 4.659 − 519 =
5. 5.773 − 499 =
6. 6.507 − 489 =
7. 7.879 − 297 =
8. 8.826 − 197 =
9. 9.734 − 239 =
10. 10.967 − 278 =
11. 11.789 − 479 =
12. 12.922 − 699 =
13. 13.521 − 268 =
14. 14.658 − 299 =
15. 15.916 − 798 =
16. 16.949 − 638 =
17. 17.798 − 339 =
18. 18.834 − 349 =
19. 19.985 − 509 =
20. 20.563 − 537 =
21. 21.821 − 797 =
22. 22.903 − 499 =
23. 23.341 − 299 =
24. 24.485 − 248 =
25. 25.755 − 398 =
26. 26.807 − 529 =
27. 27.887 − 678 =
28. 28.864 − 298 =
29. 29.600 − 497 =
30. 30.855 − 687 =
31. 31.841 − 399 =
32. 32.671 − 319 =
33. 33.610 − 548 =
34. 34.984 − 299 =
35. 35.881 − 597 =
36. 36.722 − 198 =
37. 37.499 − 297 =
38. 38.829 − 197 =
39. 39.476 − 197 =
40. 40.282 − 199 =

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