Alright, let's solve this math problem step by step. First, we have the number 637. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 123. So, we're going to take the number 637 and add it to itself 123 times.
Step 1: 0 + 637 = 637
Step 2: 637 + 637 = 1274
Step 3: 1274 + 637 = 1911
Step 4: 1911 + 637 = 2548
Step 5: 2548 + 637 = 3185
Step 6: 3185 + 637 = 3822
Step 7: 3822 + 637 = 4459
Step 8: 4459 + 637 = 5096
Step 9: 5096 + 637 = 5733
Step 10: 5733 + 637 = 6370
Step 11: 6370 + 637 = 7007
Step 12: 7007 + 637 = 7644
Step 13: 7644 + 637 = 8281
Step 14: 8281 + 637 = 8918
Step 15: 8918 + 637 = 9555
Step 16: 9555 + 637 = 10192
Step 17: 10192 + 637 = 10829
Step 18: 10829 + 637 = 11466
Step 19: 11466 + 637 = 12103
Step 20: 12103 + 637 = 12740
Step 21: 12740 + 637 = 13377
Step 22: 13377 + 637 = 14014
Step 23: 14014 + 637 = 14651
Step 24: 14651 + 637 = 15288
Step 25: 15288 + 637 = 15925
Step 26: 15925 + 637 = 16562
Step 27: 16562 + 637 = 17199
Step 28: 17199 + 637 = 17836
Step 29: 17836 + 637 = 18473
Step 30: 18473 + 637 = 19110
Step 31: 19110 + 637 = 19747
Step 32: 19747 + 637 = 20384
Step 33: 20384 + 637 = 21021
Step 34: 21021 + 637 = 21658
Step 35: 21658 + 637 = 22295
Step 36: 22295 + 637 = 22932
Step 37: 22932 + 637 = 23569
Step 38: 23569 + 637 = 24206
Step 39: 24206 + 637 = 24843
Step 40: 24843 + 637 = 25480
Step 41: 25480 + 637 = 26117
Step 42: 26117 + 637 = 26754
Step 43: 26754 + 637 = 27391
Step 44: 27391 + 637 = 28028
Step 45: 28028 + 637 = 28665
Step 46: 28665 + 637 = 29302
Step 47: 29302 + 637 = 29939
Step 48: 29939 + 637 = 30576
Step 49: 30576 + 637 = 31213
Step 50: 31213 + 637 = 31850
Step 51: 31850 + 637 = 32487
Step 52: 32487 + 637 = 33124
Step 53: 33124 + 637 = 33761
Step 54: 33761 + 637 = 34398
Step 55: 34398 + 637 = 35035
Step 56: 35035 + 637 = 35672
Step 57: 35672 + 637 = 36309
Step 58: 36309 + 637 = 36946
Step 59: 36946 + 637 = 37583
Step 60: 37583 + 637 = 38220
Step 61: 38220 + 637 = 38857
Step 62: 38857 + 637 = 39494
Step 63: 39494 + 637 = 40131
Step 64: 40131 + 637 = 40768
Step 65: 40768 + 637 = 41405
Step 66: 41405 + 637 = 42042
Step 67: 42042 + 637 = 42679
Step 68: 42679 + 637 = 43316
Step 69: 43316 + 637 = 43953
Step 70: 43953 + 637 = 44590
Step 71: 44590 + 637 = 45227
Step 72: 45227 + 637 = 45864
Step 73: 45864 + 637 = 46501
Step 74: 46501 + 637 = 47138
Step 75: 47138 + 637 = 47775
Step 76: 47775 + 637 = 48412
Step 77: 48412 + 637 = 49049
Step 78: 49049 + 637 = 49686
Step 79: 49686 + 637 = 50323
Step 80: 50323 + 637 = 50960
Step 81: 50960 + 637 = 51597
Step 82: 51597 + 637 = 52234
Step 83: 52234 + 637 = 52871
Step 84: 52871 + 637 = 53508
Step 85: 53508 + 637 = 54145
Step 86: 54145 + 637 = 54782
Step 87: 54782 + 637 = 55419
Step 88: 55419 + 637 = 56056
Step 89: 56056 + 637 = 56693
Step 90: 56693 + 637 = 57330
Step 91: 57330 + 637 = 57967
Step 92: 57967 + 637 = 58604
Step 93: 58604 + 637 = 59241
Step 94: 59241 + 637 = 59878
Step 95: 59878 + 637 = 60515
Step 96: 60515 + 637 = 61152
Step 97: 61152 + 637 = 61789
Step 98: 61789 + 637 = 62426
Step 99: 62426 + 637 = 63063
Step 100: 63063 + 637 = 63700
Step 101: 63700 + 637 = 64337
Step 102: 64337 + 637 = 64974
Step 103: 64974 + 637 = 65611
Step 104: 65611 + 637 = 66248
Step 105: 66248 + 637 = 66885
Step 106: 66885 + 637 = 67522
Step 107: 67522 + 637 = 68159
Step 108: 68159 + 637 = 68796
Step 109: 68796 + 637 = 69433
Step 110: 69433 + 637 = 70070
Step 111: 70070 + 637 = 70707
Step 112: 70707 + 637 = 71344
Step 113: 71344 + 637 = 71981
Step 114: 71981 + 637 = 72618
Step 115: 72618 + 637 = 73255
Step 116: 73255 + 637 = 73892
Step 117: 73892 + 637 = 74529
Step 118: 74529 + 637 = 75166
Step 119: 75166 + 637 = 75803
Step 120: 75803 + 637 = 76440
Step 121: 76440 + 637 = 77077
Step 122: 77077 + 637 = 77714
Step 123: 77714 + 637 = 78351

So, 637*123 = 78351