Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 899 · 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. 1.742 − 477 =
2. 2.388 − 298 =
3. 3.307 − 198 =
4. 4.372 − 128 =
5. 5.506 − 309 =
6. 6.412 − 158 =
7. 7.515 − 497 =
8. 8.722 − 559 =
9. 9.692 − 597 =
10. 10.598 − 529 =
11. 11.272 − 187 =
12. 12.987 − 397 =
13. 13.974 − 799 =
14. 14.984 − 298 =
15. 15.713 − 198 =
16. 16.593 − 557 =
17. 17.243 − 168 =
18. 18.900 − 519 =
19. 19.835 − 157 =
20. 20.350 − 239 =
21. 21.644 − 499 =
22. 22.870 − 799 =
23. 23.897 − 797 =
24. 24.536 − 317 =
25. 25.683 − 198 =
26. 26.849 − 799 =
27. 27.886 − 799 =
28. 28.748 − 597 =
29. 29.251 − 199 =
30. 30.745 − 508 =
31. 31.366 − 228 =
32. 32.669 − 499 =
33. 33.688 − 399 =
34. 34.836 − 397 =
35. 35.481 − 198 =
36. 36.891 − 687 =
37. 37.598 − 448 =
38. 38.930 − 599 =
39. 39.237 − 199 =
40. 40.996 − 638 =

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