Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 464 · 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. 1.951 − 599 =
2. 2.473 − 437 =
3. 3.531 − 199 =
4. 4.392 − 299 =
5. 5.830 − 799 =
6. 6.850 − 299 =
7. 7.587 − 348 =
8. 8.942 − 699 =
9. 9.597 − 457 =
10. 10.555 − 198 =
11. 11.224 − 187 =
12. 12.471 − 297 =
13. 13.671 − 597 =
14. 14.825 − 798 =
15. 15.852 − 399 =
16. 16.886 − 798 =
17. 17.960 − 799 =
18. 18.671 − 598 =
19. 19.983 − 697 =
20. 20.907 − 499 =
21. 21.483 − 398 =
22. 22.374 − 199 =
23. 23.640 − 198 =
24. 24.837 − 279 =
25. 25.458 − 387 =
26. 26.683 − 597 =
27. 27.971 − 798 =
28. 28.703 − 599 =
29. 29.733 − 339 =
30. 30.315 − 299 =
31. 31.241 − 197 =
32. 32.618 − 198 =
33. 33.789 − 359 =
34. 34.569 − 297 =
35. 35.847 − 797 =
36. 36.353 − 159 =
37. 37.736 − 697 =
38. 38.765 − 227 =
39. 39.781 − 597 =
40. 40.791 − 699 =

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