Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 578 · 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. 1.707 − 628 =
2. 2.901 − 389 =
3. 3.490 − 228 =
4. 4.984 − 649 =
5. 5.415 − 297 =
6. 6.741 − 298 =
7. 7.586 − 299 =
8. 8.674 − 549 =
9. 9.917 − 538 =
10. 10.919 − 299 =
11. 11.335 − 298 =
12. 12.810 − 667 =
13. 13.826 − 319 =
14. 14.423 − 397 =
15. 15.610 − 508 =
16. 16.727 − 228 =
17. 17.897 − 397 =
18. 18.934 − 499 =
19. 19.255 − 198 =
20. 20.476 − 309 =
21. 21.649 − 247 =
22. 22.713 − 657 =
23. 23.563 − 467 =
24. 24.778 − 609 =
25. 25.636 − 269 =
26. 26.823 − 448 =
27. 27.484 − 298 =
28. 28.543 − 529 =
29. 29.739 − 199 =
30. 30.860 − 798 =
31. 31.654 − 197 =
32. 32.789 − 298 =
33. 33.839 − 629 =
34. 34.434 − 397 =
35. 35.587 − 569 =
36. 36.681 − 649 =
37. 37.717 − 698 =
38. 38.833 − 799 =
39. 39.993 − 469 =
40. 40.682 − 578 =

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