Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 598 · 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. 1.219 − 199 =
2. 2.971 − 249 =
3. 3.949 − 798 =
4. 4.862 − 699 =
5. 5.752 − 658 =
6. 6.794 − 487 =
7. 7.239 − 197 =
8. 8.966 − 548 =
9. 9.674 − 599 =
10. 10.894 − 648 =
11. 11.990 − 798 =
12. 12.628 − 397 =
13. 13.770 − 398 =
14. 14.370 − 179 =
15. 15.697 − 498 =
16. 16.842 − 797 =
17. 17.880 − 799 =
18. 18.768 − 567 =
19. 19.784 − 297 =
20. 20.909 − 799 =
21. 21.387 − 289 =
22. 22.961 − 349 =
23. 23.816 − 697 =
24. 24.852 − 197 =
25. 25.259 − 197 =
26. 26.970 − 298 =
27. 27.242 − 147 =
28. 28.998 − 799 =
29. 29.528 − 399 =
30. 30.982 − 698 =
31. 31.431 − 218 =
32. 32.724 − 597 =
33. 33.740 − 678 =
34. 34.556 − 148 =
35. 35.339 − 198 =
36. 36.857 − 797 =
37. 37.760 − 299 =
38. 38.418 − 298 =
39. 39.892 − 378 =
40. 40.962 − 197 =

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