Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 286 · 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. 1.983 − 199 =
2. 2.599 − 557 =
3. 3.837 − 449 =
4. 4.639 − 469 =
5. 5.898 − 189 =
6. 6.532 − 297 =
7. 7.793 − 218 =
8. 8.696 − 397 =
9. 9.744 − 699 =
10. 10.877 − 797 =
11. 11.560 − 199 =
12. 12.600 − 199 =
13. 13.436 − 368 =
14. 14.730 − 258 =
15. 15.919 − 497 =
16. 16.783 − 498 =
17. 17.922 − 499 =
18. 18.585 − 259 =
19. 19.833 − 597 =
20. 20.451 − 397 =
21. 21.289 − 157 =
22. 22.857 − 299 =
23. 23.679 − 597 =
24. 24.951 − 128 =
25. 25.939 − 128 =
26. 26.438 − 297 =
27. 27.934 − 597 =
28. 28.963 − 799 =
29. 29.531 − 149 =
30. 30.552 − 297 =
31. 31.895 − 697 =
32. 32.912 − 799 =
33. 33.646 − 198 =
34. 34.760 − 597 =
35. 35.949 − 498 =
36. 36.891 − 529 =
37. 37.851 − 398 =
38. 38.673 − 639 =
39. 39.970 − 799 =
40. 40.408 − 199 =

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