Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 484 · 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. 1.484 − 368 =
2. 2.553 − 298 =
3. 3.641 − 299 =
4. 4.787 − 399 =
5. 5.858 − 197 =
6. 6.692 − 597 =
7. 7.978 − 599 =
8. 8.518 − 397 =
9. 9.650 − 497 =
10. 10.314 − 198 =
11. 11.785 − 499 =
12. 12.361 − 297 =
13. 13.713 − 578 =
14. 14.829 − 149 =
15. 15.578 − 198 =
16. 16.415 − 257 =
17. 17.807 − 499 =
18. 18.534 − 498 =
19. 19.732 − 487 =
20. 20.748 − 417 =
21. 21.941 − 129 =
22. 22.840 − 799 =
23. 23.766 − 198 =
24. 24.565 − 149 =
25. 25.963 − 589 =
26. 26.785 − 698 =
27. 27.859 − 798 =
28. 28.812 − 697 =
29. 29.970 − 398 =
30. 30.897 − 299 =
31. 31.679 − 397 =
32. 32.849 − 198 =
33. 33.701 − 658 =
34. 34.939 − 798 =
35. 35.933 − 799 =
36. 36.822 − 498 =
37. 37.942 − 499 =
38. 38.907 − 608 =
39. 39.640 − 429 =
40. 40.709 − 499 =

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