3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 970 · 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. 1.320 + 254 =
2. 2.318 + 196 =
3. 3.538 + 274 =
4. 4.441 − 271 =
5. 5.949 − 627 =
6. 6.219 + 191 =
7. 7.310 + 118 =
8. 8.413 − 301 =
9. 9.600 − 457 =
10. 10.704 − 145 =
11. 11.200 + 181 =
12. 12.480 + 172 =
13. 13.538 − 381 =
14. 14.450 + 422 =
15. 15.434 + 163 =
16. 16.778 + 526 =
17. 17.989 − 259 =
18. 18.293 + 399 =
19. 19.955 − 777 =
20. 20.718 − 126 =
21. 21.229 + 128 =
22. 22.622 − 345 =
23. 23.765 − 161 =
24. 24.156 + 176 =
25. 25.768 − 646 =
26. 26.828 − 561 =
27. 27.573 − 179 =
28. 28.434 + 517 =
29. 29.367 + 114 =
30. 30.509 + 358 =
31. 31.467 + 366 =
32. 32.343 + 149 =
33. 33.576 − 271 =
34. 34.916 − 538 =
35. 35.658 − 424 =
36. 36.221 + 153 =
37. 37.534 + 331 =
38. 38.661 + 162 =
39. 39.741 − 463 =
40. 40.536 + 579 =

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