Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 650 · 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. 1.644 − 127 =
2. 2.548 − 177 =
3. 3.549 − 468 =
4. 4.874 − 499 =
5. 5.927 − 287 =
6. 6.578 − 197 =
7. 7.286 − 149 =
8. 8.806 − 659 =
9. 9.625 − 397 =
10. 10.867 − 799 =
11. 11.477 − 199 =
12. 12.473 − 398 =
13. 13.724 − 697 =
14. 14.270 − 178 =
15. 15.809 − 498 =
16. 16.815 − 497 =
17. 17.952 − 589 =
18. 18.860 − 199 =
19. 19.559 − 497 =
20. 20.451 − 308 =
21. 21.587 − 318 =
22. 22.958 − 397 =
23. 23.586 − 198 =
24. 24.315 − 298 =
25. 25.776 − 598 =
26. 26.918 − 598 =
27. 27.266 − 197 =
28. 28.812 − 638 =
29. 29.867 − 197 =
30. 30.716 − 598 =
31. 31.987 − 199 =
32. 32.918 − 199 =
33. 33.912 − 437 =
34. 34.540 − 147 =
35. 35.997 − 499 =
36. 36.503 − 409 =
37. 37.460 − 399 =
38. 38.882 − 697 =
39. 39.814 − 678 =
40. 40.991 − 797 =

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