Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 791 · 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. 1.552 − 188 =
2. 2.891 − 437 =
3. 3.831 − 197 =
4. 4.738 − 497 =
5. 5.504 − 257 =
6. 6.800 − 398 =
7. 7.863 − 199 =
8. 8.789 − 497 =
9. 9.548 − 299 =
10. 10.531 − 297 =
11. 11.827 − 598 =
12. 12.514 − 398 =
13. 13.292 − 199 =
14. 14.498 − 458 =
15. 15.916 − 578 =
16. 16.529 − 258 =
17. 17.619 − 197 =
18. 18.797 − 307 =
19. 19.673 − 297 =
20. 20.646 − 629 =
21. 21.761 − 407 =
22. 22.736 − 217 =
23. 23.454 − 129 =
24. 24.261 − 119 =
25. 25.802 − 697 =
26. 26.488 − 399 =
27. 27.838 − 648 =
28. 28.807 − 488 =
29. 29.717 − 618 =
30. 30.540 − 397 =
31. 31.490 − 317 =
32. 32.685 − 649 =
33. 33.944 − 798 =
34. 34.703 − 299 =
35. 35.315 − 187 =
36. 36.909 − 699 =
37. 37.880 − 598 =
38. 38.622 − 299 =
39. 39.434 − 229 =
40. 40.691 − 497 =

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