3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 540 · 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. 1.478 − 225 =
2. 2.480 − 141 =
3. 3.272 + 675 =
4. 4.305 + 605 =
5. 5.469 − 354 =
6. 6.611 + 304 =
7. 7.170 + 246 =
8. 8.952 − 687 =
9. 9.578 − 261 =
10. 10.493 − 236 =
11. 11.623 − 112 =
12. 12.900 − 601 =
13. 13.755 + 298 =
14. 14.934 − 368 =
15. 15.538 − 275 =
16. 16.481 + 471 =
17. 17.241 + 331 =
18. 18.529 − 185 =
19. 19.592 − 192 =
20. 20.577 − 318 =
21. 21.773 − 142 =
22. 22.300 + 595 =
23. 23.529 − 228 =
24. 24.468 − 161 =
25. 25.698 + 641 =
26. 26.554 − 181 =
27. 27.923 − 646 =
28. 28.546 + 203 =
29. 29.691 + 584 =
30. 30.652 − 281 =
31. 31.870 − 231 =
32. 32.427 − 114 =
33. 33.293 + 238 =
34. 34.347 + 149 =
35. 35.700 + 515 =
36. 36.288 + 687 =
37. 37.489 + 569 =
38. 38.553 + 214 =
39. 39.971 − 771 =
40. 40.939 − 589 =

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