Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 448 · 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. 1.503 − 368 =
2. 2.386 − 239 =
3. 3.987 − 297 =
4. 4.769 − 539 =
5. 5.244 − 209 =
6. 6.801 − 248 =
7. 7.705 − 498 =
8. 8.870 − 618 =
9. 9.775 − 507 =
10. 10.895 − 587 =
11. 11.382 − 137 =
12. 12.326 − 238 =
13. 13.814 − 498 =
14. 14.910 − 599 =
15. 15.512 − 497 =
16. 16.808 − 199 =
17. 17.580 − 359 =
18. 18.244 − 118 =
19. 19.271 − 199 =
20. 20.675 − 497 =
21. 21.900 − 299 =
22. 22.947 − 697 =
23. 23.983 − 799 =
24. 24.884 − 199 =
25. 25.893 − 598 =
26. 26.638 − 597 =
27. 27.760 − 399 =
28. 28.331 − 299 =
29. 29.895 − 798 =
30. 30.803 − 538 =
31. 31.713 − 599 =
32. 32.953 − 699 =
33. 33.951 − 397 =
34. 34.426 − 177 =
35. 35.474 − 298 =
36. 36.689 − 577 =
37. 37.814 − 598 =
38. 38.926 − 797 =
39. 39.585 − 497 =
40. 40.756 − 498 =

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