Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 317 · 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. 1.557 − 539 =
2. 2.868 − 698 =
3. 3.756 − 687 =
4. 4.956 − 299 =
5. 5.738 − 398 =
6. 6.666 − 517 =
7. 7.727 − 397 =
8. 8.318 − 199 =
9. 9.610 − 257 =
10. 10.294 − 198 =
11. 11.356 − 198 =
12. 12.865 − 398 =
13. 13.591 − 397 =
14. 14.702 − 289 =
15. 15.722 − 618 =
16. 16.605 − 498 =
17. 17.883 − 299 =
18. 18.386 − 128 =
19. 19.481 − 307 =
20. 20.921 − 639 =
21. 21.390 − 197 =
22. 22.515 − 298 =
23. 23.769 − 697 =
24. 24.581 − 447 =
25. 25.658 − 529 =
26. 26.826 − 169 =
27. 27.313 − 289 =
28. 28.785 − 148 =
29. 29.894 − 398 =
30. 30.836 − 399 =
31. 31.532 − 497 =
32. 32.797 − 539 =
33. 33.258 − 199 =
34. 34.926 − 799 =
35. 35.507 − 218 =
36. 36.907 − 799 =
37. 37.621 − 599 =
38. 38.630 − 447 =
39. 39.685 − 599 =
40. 40.930 − 797 =

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