Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 194 · 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. 1.741 − 397 =
2. 2.912 − 697 =
3. 3.405 − 299 =
4. 4.981 − 679 =
5. 5.814 − 799 =
6. 6.866 − 498 =
7. 7.829 − 338 =
8. 8.603 − 299 =
9. 9.369 − 168 =
10. 10.621 − 269 =
11. 11.300 − 219 =
12. 12.812 − 697 =
13. 13.640 − 289 =
14. 14.214 − 119 =
15. 15.686 − 259 =
16. 16.402 − 299 =
17. 17.632 − 297 =
18. 18.945 − 698 =
19. 19.882 − 578 =
20. 20.339 − 299 =
21. 21.870 − 307 =
22. 22.778 − 698 =
23. 23.692 − 498 =
24. 24.924 − 129 =
25. 25.674 − 599 =
26. 26.974 − 798 =
27. 27.865 − 688 =
28. 28.354 − 297 =
29. 29.484 − 328 =
30. 30.447 − 299 =
31. 31.739 − 397 =
32. 32.761 − 379 =
33. 33.765 − 678 =
34. 34.953 − 798 =
35. 35.335 − 197 =
36. 36.540 − 198 =
37. 37.704 − 599 =
38. 38.694 − 199 =
39. 39.783 − 519 =
40. 40.533 − 497 =

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