Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 192 · 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. 1.692 − 598 =
2. 2.456 − 199 =
3. 3.473 − 418 =
4. 4.646 − 498 =
5. 5.498 − 289 =
6. 6.674 − 339 =
7. 7.982 − 687 =
8. 8.434 − 218 =
9. 9.840 − 699 =
10. 10.728 − 699 =
11. 11.919 − 799 =
12. 12.722 − 499 =
13. 13.428 − 197 =
14. 14.989 − 697 =
15. 15.970 − 658 =
16. 16.502 − 287 =
17. 17.843 − 799 =
18. 18.959 − 307 =
19. 19.767 − 569 =
20. 20.738 − 369 =
21. 21.637 − 567 =
22. 22.824 − 679 =
23. 23.799 − 567 =
24. 24.355 − 169 =
25. 25.318 − 179 =
26. 26.548 − 117 =
27. 27.673 − 198 =
28. 28.603 − 117 =
29. 29.672 − 479 =
30. 30.857 − 417 =
31. 31.681 − 588 =
32. 32.424 − 397 =
33. 33.974 − 169 =
34. 34.886 − 797 =
35. 35.780 − 698 =
36. 36.990 − 617 =
37. 37.842 − 799 =
38. 38.835 − 679 =
39. 39.935 − 427 =
40. 40.794 − 399 =

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