Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 988 · 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. 1.539 − 449 =
2. 2.916 − 798 =
3. 3.973 − 528 =
4. 4.864 − 797 =
5. 5.883 − 689 =
6. 6.579 − 499 =
7. 7.819 − 699 =
8. 8.865 − 399 =
9. 9.821 − 687 =
10. 10.702 − 598 =
11. 11.627 − 547 =
12. 12.819 − 697 =
13. 13.403 − 197 =
14. 14.846 − 339 =
15. 15.997 − 799 =
16. 16.465 − 298 =
17. 17.471 − 178 =
18. 18.959 − 399 =
19. 19.751 − 459 =
20. 20.362 − 199 =
21. 21.423 − 277 =
22. 22.891 − 799 =
23. 23.343 − 199 =
24. 24.710 − 497 =
25. 25.655 − 339 =
26. 26.923 − 257 =
27. 27.934 − 698 =
28. 28.855 − 399 =
29. 29.954 − 497 =
30. 30.590 − 497 =
31. 31.311 − 259 =
32. 32.521 − 249 =
33. 33.815 − 698 =
34. 34.924 − 398 =
35. 35.635 − 348 =
36. 36.259 − 219 =
37. 37.809 − 198 =
38. 38.571 − 197 =
39. 39.596 − 237 =
40. 40.938 − 798 =

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