Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 749 · 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. 1.468 − 387 =
2. 2.800 − 697 =
3. 3.903 − 797 =
4. 4.706 − 659 =
5. 5.488 − 298 =
6. 6.635 − 248 =
7. 7.658 − 399 =
8. 8.397 − 298 =
9. 9.305 − 177 =
10. 10.704 − 388 =
11. 11.845 − 678 =
12. 12.678 − 547 =
13. 13.982 − 379 =
14. 14.800 − 429 =
15. 15.804 − 697 =
16. 16.242 − 158 =
17. 17.564 − 399 =
18. 18.550 − 499 =
19. 19.593 − 199 =
20. 20.595 − 239 =
21. 21.274 − 199 =
22. 22.796 − 678 =
23. 23.547 − 398 =
24. 24.439 − 299 =
25. 25.487 − 338 =
26. 26.780 − 199 =
27. 27.685 − 298 =
28. 28.879 − 698 =
29. 29.626 − 599 =
30. 30.594 − 507 =
31. 31.888 − 298 =
32. 32.724 − 697 =
33. 33.835 − 799 =
34. 34.929 − 577 =
35. 35.983 − 558 =
36. 36.746 − 599 =
37. 37.754 − 188 =
38. 38.890 − 399 =
39. 39.703 − 278 =
40. 40.779 − 669 =

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