Adding three-digit numbers 100 to 400 (Horizontal Questions - Full Page)

This basic Addition worksheet is designed to help kids practice adding three-digit numbers (100 through 400) with addition questions that change each time you visit. This math worksheet is printable and displays a full page math sheet with Horizontal Addition questions.

With this math sheet generator, you can easily create Addition worksheets that are never the same and always different, providing you with an unlimited supply of math sheets to use in the classroom or at home.

Each math sheet also has an optional answer key checkbox that you can select, if you wish to print an answer key to go along with your math worksheet. And there are six different question styles to choose from, as listed below.

Possible Questions:

The possible addition questions on this math worksheet are:

  • 100+100, 101+100, 102+100, 103+100, 104+100, 105+100 ... 400+100
  • 100+101, 101+101, 102+101, 103+101, 104+101, 105+101 ... 400+101
  • 100+102, 101+102, 102+102, 103+102, 104+102, 105+102 ... 400+102
  • ...
  • 100+400, 101+400, 102+400, 103+400, 104+400, 105+400 ... 400+400
ANSWER KEY
269 + 394 =
 663
284 + 106 =
 390
195 + 381 =
 576
255 + 253 =
 508
169 + 236 =
 405
373 + 189 =
 562
144 + 230 =
 374
152 + 233 =
 385
227 + 336 =
 563
265 + 110 =
 375
350 + 329 =
 679
358 + 371 =
 729
179 + 347 =
 526
225 + 248 =
 473
128 + 168 =
 296
148 + 132 =
 280
215 + 256 =
 471
156 + 114 =
 270
152 + 302 =
 454
242 + 198 =
 440
248 + 261 =
 509
140 + 224 =
 364
186 + 167 =
 353
200 + 366 =
 566
164 + 128 =
 292
310 + 194 =
 504
339 + 245 =
 584
233 + 248 =
 481
211 + 145 =
 356
305 + 163 =
 468
325 + 252 =
 577
186 + 179 =
 365
311 + 298 =
 609
359 + 366 =
 725
275 + 390 =
 665
192 + 371 =
 563
185 + 266 =
 451
327 + 376 =
 703
281 + 195 =
 476
397 + 311 =
 708
309 + 327 =
 636
308 + 375 =
 683
311 + 243 =
 554
237 + 352 =
 589
349 + 345 =
 694
158 + 310 =
 468
303 + 362 =
 665
315 + 199 =
 514
390 + 252 =
 642
217 + 336 =
 553
326 + 192 =
 518
334 + 124 =
 458
164 + 258 =
 422
215 + 284 =
 499
339 + 116 =
 455
347 + 264 =
 611
358 + 254 =
 612
332 + 199 =
 531
219 + 276 =
 495
108 + 136 =
 244

 Check this box to display the answer key

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