3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 309 · 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. 1.500 − 316 =
2. 2.471 + 237 =
3. 3.467 + 144 =
4. 4.177 + 496 =
5. 5.567 − 224 =
6. 6.910 − 811 =
7. 7.678 + 401 =
8. 8.580 − 274 =
9. 9.505 + 377 =
10. 10.339 + 568 =
11. 11.455 − 271 =
12. 12.488 − 131 =
13. 13.473 − 124 =
14. 14.745 − 245 =
15. 15.456 + 119 =
16. 16.742 − 451 =
17. 17.201 + 461 =
18. 18.629 + 544 =
19. 19.596 − 195 =
20. 20.686 − 279 =
21. 21.580 + 245 =
22. 22.323 + 161 =
23. 23.289 + 351 =
24. 24.979 − 447 =
25. 25.677 + 114 =
26. 26.451 − 157 =
27. 27.724 + 451 =
28. 28.889 − 325 =
29. 29.843 − 395 =
30. 30.570 + 371 =
31. 31.969 − 522 =
32. 32.526 − 223 =
33. 33.661 − 463 =
34. 34.561 + 201 =
35. 35.459 − 119 =
36. 36.459 + 388 =
37. 37.986 − 247 =
38. 38.257 + 437 =
39. 39.468 − 356 =
40. 40.737 − 174 =

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