Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 927 · 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. 1.616 − 198 =
2. 2.805 − 248 =
3. 3.629 − 298 =
4. 4.499 − 397 =
5. 5.534 − 349 =
6. 6.949 − 298 =
7. 7.967 − 797 =
8. 8.924 − 798 =
9. 9.649 − 498 =
10. 10.692 − 299 =
11. 11.475 − 197 =
12. 12.557 − 388 =
13. 13.289 − 197 =
14. 14.387 − 188 =
15. 15.870 − 158 =
16. 16.370 − 299 =
17. 17.958 − 557 =
18. 18.704 − 609 =
19. 19.930 − 447 =
20. 20.600 − 327 =
21. 21.952 − 288 =
22. 22.773 − 568 =
23. 23.436 − 208 =
24. 24.973 − 378 =
25. 25.778 − 298 =
26. 26.740 − 328 =
27. 27.609 − 429 =
28. 28.427 − 299 =
29. 29.695 − 497 =
30. 30.627 − 177 =
31. 31.753 − 198 =
32. 32.852 − 297 =
33. 33.309 − 219 =
34. 34.485 − 299 =
35. 35.712 − 599 =
36. 36.959 − 398 =
37. 37.878 − 799 =
38. 38.492 − 477 =
39. 39.909 − 539 =
40. 40.510 − 299 =

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