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 251. So, we're going to take the number 637 and add it to itself 251 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
Step 124: 78351 + 637 = 78988
Step 125: 78988 + 637 = 79625
Step 126: 79625 + 637 = 80262
Step 127: 80262 + 637 = 80899
Step 128: 80899 + 637 = 81536
Step 129: 81536 + 637 = 82173
Step 130: 82173 + 637 = 82810
Step 131: 82810 + 637 = 83447
Step 132: 83447 + 637 = 84084
Step 133: 84084 + 637 = 84721
Step 134: 84721 + 637 = 85358
Step 135: 85358 + 637 = 85995
Step 136: 85995 + 637 = 86632
Step 137: 86632 + 637 = 87269
Step 138: 87269 + 637 = 87906
Step 139: 87906 + 637 = 88543
Step 140: 88543 + 637 = 89180
Step 141: 89180 + 637 = 89817
Step 142: 89817 + 637 = 90454
Step 143: 90454 + 637 = 91091
Step 144: 91091 + 637 = 91728
Step 145: 91728 + 637 = 92365
Step 146: 92365 + 637 = 93002
Step 147: 93002 + 637 = 93639
Step 148: 93639 + 637 = 94276
Step 149: 94276 + 637 = 94913
Step 150: 94913 + 637 = 95550
Step 151: 95550 + 637 = 96187
Step 152: 96187 + 637 = 96824
Step 153: 96824 + 637 = 97461
Step 154: 97461 + 637 = 98098
Step 155: 98098 + 637 = 98735
Step 156: 98735 + 637 = 99372
Step 157: 99372 + 637 = 100009
Step 158: 100009 + 637 = 100646
Step 159: 100646 + 637 = 101283
Step 160: 101283 + 637 = 101920
Step 161: 101920 + 637 = 102557
Step 162: 102557 + 637 = 103194
Step 163: 103194 + 637 = 103831
Step 164: 103831 + 637 = 104468
Step 165: 104468 + 637 = 105105
Step 166: 105105 + 637 = 105742
Step 167: 105742 + 637 = 106379
Step 168: 106379 + 637 = 107016
Step 169: 107016 + 637 = 107653
Step 170: 107653 + 637 = 108290
Step 171: 108290 + 637 = 108927
Step 172: 108927 + 637 = 109564
Step 173: 109564 + 637 = 110201
Step 174: 110201 + 637 = 110838
Step 175: 110838 + 637 = 111475
Step 176: 111475 + 637 = 112112
Step 177: 112112 + 637 = 112749
Step 178: 112749 + 637 = 113386
Step 179: 113386 + 637 = 114023
Step 180: 114023 + 637 = 114660
Step 181: 114660 + 637 = 115297
Step 182: 115297 + 637 = 115934
Step 183: 115934 + 637 = 116571
Step 184: 116571 + 637 = 117208
Step 185: 117208 + 637 = 117845
Step 186: 117845 + 637 = 118482
Step 187: 118482 + 637 = 119119
Step 188: 119119 + 637 = 119756
Step 189: 119756 + 637 = 120393
Step 190: 120393 + 637 = 121030
Step 191: 121030 + 637 = 121667
Step 192: 121667 + 637 = 122304
Step 193: 122304 + 637 = 122941
Step 194: 122941 + 637 = 123578
Step 195: 123578 + 637 = 124215
Step 196: 124215 + 637 = 124852
Step 197: 124852 + 637 = 125489
Step 198: 125489 + 637 = 126126
Step 199: 126126 + 637 = 126763
Step 200: 126763 + 637 = 127400
Step 201: 127400 + 637 = 128037
Step 202: 128037 + 637 = 128674
Step 203: 128674 + 637 = 129311
Step 204: 129311 + 637 = 129948
Step 205: 129948 + 637 = 130585
Step 206: 130585 + 637 = 131222
Step 207: 131222 + 637 = 131859
Step 208: 131859 + 637 = 132496
Step 209: 132496 + 637 = 133133
Step 210: 133133 + 637 = 133770
Step 211: 133770 + 637 = 134407
Step 212: 134407 + 637 = 135044
Step 213: 135044 + 637 = 135681
Step 214: 135681 + 637 = 136318
Step 215: 136318 + 637 = 136955
Step 216: 136955 + 637 = 137592
Step 217: 137592 + 637 = 138229
Step 218: 138229 + 637 = 138866
Step 219: 138866 + 637 = 139503
Step 220: 139503 + 637 = 140140
Step 221: 140140 + 637 = 140777
Step 222: 140777 + 637 = 141414
Step 223: 141414 + 637 = 142051
Step 224: 142051 + 637 = 142688
Step 225: 142688 + 637 = 143325
Step 226: 143325 + 637 = 143962
Step 227: 143962 + 637 = 144599
Step 228: 144599 + 637 = 145236
Step 229: 145236 + 637 = 145873
Step 230: 145873 + 637 = 146510
Step 231: 146510 + 637 = 147147
Step 232: 147147 + 637 = 147784
Step 233: 147784 + 637 = 148421
Step 234: 148421 + 637 = 149058
Step 235: 149058 + 637 = 149695
Step 236: 149695 + 637 = 150332
Step 237: 150332 + 637 = 150969
Step 238: 150969 + 637 = 151606
Step 239: 151606 + 637 = 152243
Step 240: 152243 + 637 = 152880
Step 241: 152880 + 637 = 153517
Step 242: 153517 + 637 = 154154
Step 243: 154154 + 637 = 154791
Step 244: 154791 + 637 = 155428
Step 245: 155428 + 637 = 156065
Step 246: 156065 + 637 = 156702
Step 247: 156702 + 637 = 157339
Step 248: 157339 + 637 = 157976
Step 249: 157976 + 637 = 158613
Step 250: 158613 + 637 = 159250
Step 251: 159250 + 637 = 159887

So, 637*251 = 159887