Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 586 · 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. 1.343 − 189 =
2. 2.974 − 199 =
3. 3.557 − 118 =
4. 4.799 − 297 =
5. 5.339 − 258 =
6. 6.710 − 449 =
7. 7.750 − 699 =
8. 8.790 − 698 =
9. 9.923 − 799 =
10. 10.436 − 399 =
11. 11.986 − 279 =
12. 12.775 − 599 =
13. 13.688 − 599 =
14. 14.688 − 299 =
15. 15.231 − 148 =
16. 16.778 − 497 =
17. 17.695 − 659 =
18. 18.716 − 129 =
19. 19.812 − 648 =
20. 20.933 − 399 =
21. 21.643 − 599 =
22. 22.776 − 647 =
23. 23.867 − 639 =
24. 24.724 − 599 =
25. 25.475 − 297 =
26. 26.859 − 297 =
27. 27.938 − 417 =
28. 28.669 − 599 =
29. 29.520 − 238 =
30. 30.883 − 498 =
31. 31.633 − 308 =
32. 32.793 − 499 =
33. 33.427 − 397 =
34. 34.783 − 697 =
35. 35.294 − 227 =
36. 36.537 − 399 =
37. 37.609 − 399 =
38. 38.670 − 299 =
39. 39.753 − 299 =
40. 40.748 − 698 =

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