Question

Find the sum of all whole numbers whose digits are strictly increasing?

Examples of such numbers are 5, 379, and 12345789
Some non-examples are 22, 102, and 123456798

Answer 1

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 + 23 + 24 + 25 + 26 + 27 + 28 + 29 + 34 + 35 + 36 + 37 + 38 + 39 + 45 + 46 + 47 + 48 + 49 + 56 + 57 + 58 + 59 + 67 + 68 + 69 + 78 + 79 + 89 + 123 + 124 + 125 + 126 + 127 + 128 + 129 + 134 + 135 + 136 + 137 + 138 + 139 + 145 + 146 + 147 + 148 + 149 + 156 + 157 + 158 + 159 + 167 + 168 + 169 + 178 + 179 + 189 + 234 + 235 + 236 + 237 + 238 + 239 + 245 + 246 + 247 + 248 + 249 + 256 + 257 + 258 + 259 + 267 + 268 + 269 + 278 + 279 + 289 + 345 + 346 + 347 + 348 + 349 + 356 + 357 + 358 + 359 + 367 + 368 + 369 + 378 + 379 + 389 + 456 + 457 + 458 + 459 + 467 + 468 + 469 + 478 + 479 + 489 + 567 + 568 + 569 + 578 + 579 + 589 + 678 + 679 + 689 + 789 + 1234 + 1235 + 1236 + 1237 + 1238 + 1239 + 1245 + 1246 + 1247 + 1248 + 1249 + 1256 + 1257 + 1258 + 1259 + 1267 + 1268 + 1269 + 1278 + 1279 + 1289 + 1345 + 1346 + 1347 + 1348 + 1349 + 1356 + 1357 + 1358 + 1359 + 1367 + 1368 + 1369 + 1378 + 1379 + 1389 + 1456 + 1457 + 1458 + 1459 + 1467 + 1468 + 1469 + 1478 + 1479 + 1489 + 1567 + 1568 + 1569 + 1578 + 1579 + 1589 + 1678 + 1679 + 1689 + 1789 + 2345 + 2346 + 2347 + 2348 + 2349 + 2356 + 2357 + 2358 + 2359 + 2367 + 2368 + 2369 + 2378 + 2379 + 2389 + 2456 + 2457 + 2458 + 2459 + 2467 + 2468 + 2469 + 2478 + 2479 + 2489 + 2567 + 2568 + 2569 + 2578 + 2579 + 2589 + 2678 + 2679 + 2689 + 2789 + 3456 + 3457 + 3458 + 3459 + 3467 + 3468 + 3469 + 3478 + 3479 + 3489 + 3567 + 3568 + 3569 + 3578 + 3579 + 3589 + 3678 + 3679 + 3689 + 3789 + 4567 + 4568 + 4569 + 4578 + 4579 + 4589 + 4678 + 4679 + 4689 + 4789 + 5678 + 5679 + 5689 + 5789 + 6789 + 12345 + 12346 + 12347 + 12348 + 12349 + 12356 + 12357 + 12358 + 12359 + 12367 + 12368 + 12369 + 12378 + 12379 + 12389 + 12456 + 12457 + 12458 + 12459 + 12467 + 12468 + 12469 + 12478 + 12479 + 12489 + 12567 + 12568 + 12569 + 12578 + 12579 + 12589 + 12678 + 12679 + 12689 + 12789 + 13456 + 13457 + 13458 + 13459 + 13467 + 13468 + 13469 + 13478 + 13479 + 13489 + 13567 + 13568 + 13569 + 13578 + 13579 + 13589 + 13678 + 13679 + 13689 + 13789 + 14567 + 14568 + 14569 + 14578 + 14579 + 14589 + 14678 + 14679 + 14689 + 14789 + 15678 + 15679 + 15689 + 15789 + 16789 + 23456 + 23457 + 23458 + 23459 + 23467 + 23468 + 23469 + 23478 + 23479 + 23489 + 23567 + 23568 + 23569 + 23578 + 23579 + 23589 + 23678 + 23679 + 23689 + 23789 + 24567 + 24568 + 24569 + 24578 + 24579 + 24589 + 24678 + 24679 + 24689 + 24789 + 25678 + 25679 + 25689 + 25789 + 26789 + 34567 + 34568 + 34569 + 34578 + 34579 + 34589 + 34678 + 34679 + 34689 + 34789 + 35678 + 35679 + 35689 + 35789 + 36789 + 45678 + 45679 + 45689 + 45789 + 46789 + 56789 + 123456 + 123457 + 123458 + 123459 + 123467 + 123468 + 123469 + 123478 + 123479 + 123489 + 123567 + 123568 + 123569 + 123578 + 123579 + 123589 + 123678 + 123679 + 123689 + 123789 + 124567 + 124568 + 124569 + 124578 + 124579 + 124589 + 124678 + 124679 + 124689 + 124789 + 125678 + 125679 + 125689 + 125789 + 126789 + 134567 + 134568 + 134569 + 134578 + 134579 + 134589 + 134678 + 134679 + 134689 + 134789 + 135678 + 135679 + 135689 + 135789 + 136789 + 145678 + 145679 + 145689 + 145789 + 146789 + 156789 + 234567 + 234568 + 234569 + 234578 + 234579 + 234589 + 234678 + 234679 + 234689 + 234789 + 235678 + 235679 + 235689 + 235789 + 236789 + 245678 + 245679 + 245689 + 245789 + 246789 + 256789 + 345678 + 345679 + 345689 + 345789 + 346789 + 356789 + 456789 + 1234567 + 1234568 + 1234569 + 1234578 + 1234579 + 1234589 + 1234678 + 1234679 + 1234689 + 1234789 + 1235678 + 1235679 + 1235689 + 1235789 + 1236789 + 1245678 + 1245679 + 1245689 + 1245789 + 1246789 + 1256789 + 1345678 + 1345679 + 1345689 + 1345789 + 1346789 + 1356789 + 1456789 + 2345678 + 2345679 + 2345689 + 2345789 + 2346789 + 2356789 + 2456789 + 3456789 + 12345678 + 12345679 + 12345689 + 12345789 + 12346789 + 12356789 + 12456789 + 13456789 + 23456789 + 123456789 = 320214537.