3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 855 · 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. 1.463 − 291 =
2. 2.511 − 265 =
3. 3.337 + 365 =
4. 4.976 − 145 =
5. 5.550 + 585 =
6. 6.207 + 635 =
7. 7.677 − 203 =
8. 8.716 − 217 =
9. 9.676 + 301 =
10. 10.910 − 253 =
11. 11.524 − 132 =
12. 12.412 + 158 =
13. 13.606 − 441 =
14. 14.279 + 213 =
15. 15.510 + 239 =
16. 16.800 − 112 =
17. 17.743 − 213 =
18. 18.823 − 127 =
19. 19.280 + 123 =
20. 20.151 + 201 =
21. 21.338 + 174 =
22. 22.396 + 134 =
23. 23.900 − 205 =
24. 24.494 + 123 =
25. 25.595 + 585 =
26. 26.463 − 346 =
27. 27.567 + 596 =
28. 28.787 − 527 =
29. 29.244 + 539 =
30. 30.680 + 526 =
31. 31.744 − 322 =
32. 32.774 − 655 =
33. 33.576 − 428 =
34. 34.336 + 498 =
35. 35.757 + 207 =
36. 36.476 − 374 =
37. 37.576 + 116 =
38. 38.579 + 596 =
39. 39.540 − 141 =
40. 40.906 − 621 =

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