Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 398 · 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. 1.187 − 119 =
2. 2.938 − 298 =
3. 3.831 − 299 =
4. 4.504 − 198 =
5. 5.506 − 398 =
6. 6.855 − 269 =
7. 7.483 − 417 =
8. 8.489 − 298 =
9. 9.934 − 667 =
10. 10.693 − 488 =
11. 11.669 − 598 =
12. 12.351 − 298 =
13. 13.358 − 208 =
14. 14.311 − 129 =
15. 15.889 − 297 =
16. 16.910 − 529 =
17. 17.983 − 597 =
18. 18.857 − 669 =
19. 19.966 − 597 =
20. 20.394 − 197 =
21. 21.795 − 658 =
22. 22.654 − 618 =
23. 23.858 − 667 =
24. 24.999 − 797 =
25. 25.445 − 217 =
26. 26.666 − 439 =
27. 27.544 − 328 =
28. 28.772 − 518 =
29. 29.797 − 197 =
30. 30.514 − 497 =
31. 31.908 − 697 =
32. 32.866 − 798 =
33. 33.961 − 799 =
34. 34.668 − 528 =
35. 35.640 − 597 =
36. 36.998 − 697 =
37. 37.772 − 499 =
38. 38.506 − 419 =
39. 39.798 − 679 =
40. 40.901 − 798 =

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths