Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 673 · 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. 1.668 − 419 =
2. 2.795 − 307 =
3. 3.734 − 497 =
4. 4.733 − 467 =
5. 5.763 − 377 =
6. 6.280 − 148 =
7. 7.392 − 197 =
8. 8.960 − 497 =
9. 9.890 − 569 =
10. 10.855 − 798 =
11. 11.712 − 588 =
12. 12.784 − 698 =
13. 13.799 − 598 =
14. 14.516 − 297 =
15. 15.748 − 597 =
16. 16.879 − 449 =
17. 17.465 − 307 =
18. 18.853 − 478 =
19. 19.783 − 698 =
20. 20.727 − 689 =
21. 21.934 − 147 =
22. 22.621 − 398 =
23. 23.932 − 459 =
24. 24.267 − 227 =
25. 25.480 − 297 =
26. 26.856 − 377 =
27. 27.955 − 217 =
28. 28.867 − 199 =
29. 29.828 − 499 =
30. 30.874 − 599 =
31. 31.993 − 298 =
32. 32.968 − 649 =
33. 33.737 − 698 =
34. 34.933 − 299 =
35. 35.521 − 199 =
36. 36.297 − 179 =
37. 37.963 − 199 =
38. 38.688 − 597 =
39. 39.626 − 609 =
40. 40.981 − 638 =

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