Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 281 · 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. 1.384 − 227 =
2. 2.865 − 638 =
3. 3.567 − 388 =
4. 4.754 − 528 =
5. 5.731 − 698 =
6. 6.510 − 198 =
7. 7.888 − 699 =
8. 8.650 − 448 =
9. 9.833 − 648 =
10. 10.877 − 797 =
11. 11.736 − 699 =
12. 12.344 − 218 =
13. 13.713 − 398 =
14. 14.441 − 399 =
15. 15.611 − 498 =
16. 16.935 − 539 =
17. 17.409 − 217 =
18. 18.526 − 508 =
19. 19.386 − 188 =
20. 20.581 − 308 =
21. 21.756 − 698 =
22. 22.878 − 798 =
23. 23.920 − 698 =
24. 24.752 − 698 =
25. 25.953 − 797 =
26. 26.596 − 198 =
27. 27.891 − 408 =
28. 28.840 − 228 =
29. 29.324 − 298 =
30. 30.934 − 697 =
31. 31.942 − 157 =
32. 32.857 − 799 =
33. 33.832 − 277 =
34. 34.947 − 647 =
35. 35.795 − 257 =
36. 36.709 − 399 =
37. 37.951 − 398 =
38. 38.814 − 599 =
39. 39.987 − 498 =
40. 40.770 − 609 =

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