Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 246 · 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. 1.928 − 217 =
2. 2.728 − 697 =
3. 3.961 − 397 =
4. 4.574 − 199 =
5. 5.235 − 118 =
6. 6.369 − 297 =
7. 7.746 − 599 =
8. 8.944 − 398 =
9. 9.869 − 699 =
10. 10.677 − 548 =
11. 11.577 − 438 =
12. 12.626 − 198 =
13. 13.605 − 539 =
14. 14.249 − 198 =
15. 15.553 − 478 =
16. 16.946 − 399 =
17. 17.902 − 798 =
18. 18.456 − 438 =
19. 19.461 − 339 =
20. 20.979 − 607 =
21. 21.676 − 578 =
22. 22.181 − 148 =
23. 23.747 − 319 =
24. 24.596 − 258 =
25. 25.859 − 599 =
26. 26.739 − 619 =
27. 27.993 − 557 =
28. 28.719 − 379 =
29. 29.959 − 797 =
30. 30.828 − 397 =
31. 31.884 − 558 =
32. 32.506 − 287 =
33. 33.774 − 599 =
34. 34.411 − 258 =
35. 35.959 − 497 =
36. 36.936 − 299 =
37. 37.857 − 337 =
38. 38.723 − 397 =
39. 39.877 − 198 =
40. 40.890 − 497 =

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