Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 712 · 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. 1.701 − 528 =
2. 2.549 − 497 =
3. 3.780 − 569 =
4. 4.836 − 298 =
5. 5.463 − 198 =
6. 6.898 − 438 =
7. 7.883 − 797 =
8. 8.929 − 438 =
9. 9.507 − 397 =
10. 10.962 − 438 =
11. 11.509 − 308 =
12. 12.943 − 199 =
13. 13.314 − 177 =
14. 14.978 − 297 =
15. 15.965 − 397 =
16. 16.488 − 199 =
17. 17.925 − 799 =
18. 18.750 − 698 =
19. 19.513 − 397 =
20. 20.741 − 698 =
21. 21.452 − 129 =
22. 22.971 − 498 =
23. 23.779 − 688 =
24. 24.645 − 498 =
25. 25.602 − 198 =
26. 26.897 − 688 =
27. 27.732 − 208 =
28. 28.650 − 599 =
29. 29.487 − 329 =
30. 30.625 − 429 =
31. 31.867 − 227 =
32. 32.850 − 647 =
33. 33.583 − 398 =
34. 34.896 − 598 =
35. 35.856 − 599 =
36. 36.772 − 308 =
37. 37.805 − 398 =
38. 38.857 − 417 =
39. 39.950 − 798 =
40. 40.923 − 288 =

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