3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 423 · 40 questions

How to do it in your head (Hundreds first): Keep the first number as it is and split the second into hundreds, tens and ones. Add (or take away) the hundreds first, then the tens. Finish with the ones — bridge through a ten if you need to.

1. 1.448 − 272 =
2. 2.502 − 159 =
3. 3.434 + 123 =
4. 4.718 + 686 =
5. 5.479 + 219 =
6. 6.311 + 416 =
7. 7.427 − 301 =
8. 8.264 + 156 =
9. 9.418 + 305 =
10. 10.417 − 133 =
11. 11.750 − 599 =
12. 12.532 − 161 =
13. 13.480 + 535 =
14. 14.678 + 682 =
15. 15.807 − 357 =
16. 16.845 − 592 =
17. 17.854 − 699 =
18. 18.671 + 252 =
19. 19.419 − 198 =
20. 20.861 − 285 =
21. 21.269 + 568 =
22. 22.465 + 362 =
23. 23.942 − 346 =
24. 24.214 + 158 =
25. 25.429 − 174 =
26. 26.447 − 159 =
27. 27.592 + 605 =
28. 28.286 + 218 =
29. 29.153 + 577 =
30. 30.413 + 257 =
31. 31.485 − 385 =
32. 32.704 − 244 =
33. 33.720 + 457 =
34. 34.559 − 451 =
35. 35.793 − 581 =
36. 36.588 − 136 =
37. 37.911 − 724 =
38. 38.517 + 212 =
39. 39.590 + 152 =
40. 40.721 − 451 =

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