3-Digit Mental Addition and Subtraction Worksheet
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.
NameDateTime takenScore ___ / 40
- 1.493 − 276 =
- 2.549 + 583 =
- 3.652 + 116 =
- 4.699 − 199 =
- 5.182 + 472 =
- 6.415 − 274 =
- 7.281 + 277 =
- 8.722 + 495 =
- 9.802 − 622 =
- 10.179 + 642 =
- 11.858 − 532 =
- 12.787 − 454 =
- 13.148 + 582 =
- 14.148 + 304 =
- 15.213 + 456 =
- 16.682 − 429 =
- 17.168 + 525 =
- 18.276 + 341 =
- 19.235 + 312 =
- 20.444 + 296 =
- 21.920 − 261 =
- 22.531 − 184 =
- 23.742 − 618 =
- 24.138 + 251 =
- 25.133 + 159 =
- 26.884 − 182 =
- 27.758 + 221 =
- 28.513 − 405 =
- 29.986 − 551 =
- 30.415 − 141 =
- 31.649 − 247 =
- 32.717 − 349 =
- 33.667 − 476 =
- 34.319 + 207 =
- 35.622 + 197 =
- 36.632 + 266 =
- 37.540 − 288 =
- 38.499 − 292 =
- 39.748 + 501 =
- 40.686 + 538 =
Answer key
- 217
- 1132
- 768
- 500
- 654
- 141
- 558
- 1217
- 180
- 821
- 326
- 333
- 730
- 452
- 669
- 253
- 693
- 617
- 547
- 740
- 659
- 347
- 124
- 389
- 292
- 702
- 979
- 108
- 435
- 274
- 402
- 368
- 191
- 526
- 819
- 898
- 252
- 207
- 1249
- 1224
Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths