Let's roll up our sleeves and solve this. We have 42 and we're going to multiply it by 248, essentially adding 42 to itself 248 times.
Step 1: 0 + 42 = 42
Step 2: 42 + 42 = 84
Step 3: 84 + 42 = 126
Step 4: 126 + 42 = 168
Step 5: 168 + 42 = 210
Step 6: 210 + 42 = 252
Step 7: 252 + 42 = 294
Step 8: 294 + 42 = 336
Step 9: 336 + 42 = 378
Step 10: 378 + 42 = 420
Step 11: 420 + 42 = 462
Step 12: 462 + 42 = 504
Step 13: 504 + 42 = 546
Step 14: 546 + 42 = 588
Step 15: 588 + 42 = 630
Step 16: 630 + 42 = 672
Step 17: 672 + 42 = 714
Step 18: 714 + 42 = 756
Step 19: 756 + 42 = 798
Step 20: 798 + 42 = 840
Step 21: 840 + 42 = 882
Step 22: 882 + 42 = 924
Step 23: 924 + 42 = 966
Step 24: 966 + 42 = 1008
Step 25: 1008 + 42 = 1050
Step 26: 1050 + 42 = 1092
Step 27: 1092 + 42 = 1134
Step 28: 1134 + 42 = 1176
Step 29: 1176 + 42 = 1218
Step 30: 1218 + 42 = 1260
Step 31: 1260 + 42 = 1302
Step 32: 1302 + 42 = 1344
Step 33: 1344 + 42 = 1386
Step 34: 1386 + 42 = 1428
Step 35: 1428 + 42 = 1470
Step 36: 1470 + 42 = 1512
Step 37: 1512 + 42 = 1554
Step 38: 1554 + 42 = 1596
Step 39: 1596 + 42 = 1638
Step 40: 1638 + 42 = 1680
Step 41: 1680 + 42 = 1722
Step 42: 1722 + 42 = 1764
Step 43: 1764 + 42 = 1806
Step 44: 1806 + 42 = 1848
Step 45: 1848 + 42 = 1890
Step 46: 1890 + 42 = 1932
Step 47: 1932 + 42 = 1974
Step 48: 1974 + 42 = 2016
Step 49: 2016 + 42 = 2058
Step 50: 2058 + 42 = 2100
Step 51: 2100 + 42 = 2142
Step 52: 2142 + 42 = 2184
Step 53: 2184 + 42 = 2226
Step 54: 2226 + 42 = 2268
Step 55: 2268 + 42 = 2310
Step 56: 2310 + 42 = 2352
Step 57: 2352 + 42 = 2394
Step 58: 2394 + 42 = 2436
Step 59: 2436 + 42 = 2478
Step 60: 2478 + 42 = 2520
Step 61: 2520 + 42 = 2562
Step 62: 2562 + 42 = 2604
Step 63: 2604 + 42 = 2646
Step 64: 2646 + 42 = 2688
Step 65: 2688 + 42 = 2730
Step 66: 2730 + 42 = 2772
Step 67: 2772 + 42 = 2814
Step 68: 2814 + 42 = 2856
Step 69: 2856 + 42 = 2898
Step 70: 2898 + 42 = 2940
Step 71: 2940 + 42 = 2982
Step 72: 2982 + 42 = 3024
Step 73: 3024 + 42 = 3066
Step 74: 3066 + 42 = 3108
Step 75: 3108 + 42 = 3150
Step 76: 3150 + 42 = 3192
Step 77: 3192 + 42 = 3234
Step 78: 3234 + 42 = 3276
Step 79: 3276 + 42 = 3318
Step 80: 3318 + 42 = 3360
Step 81: 3360 + 42 = 3402
Step 82: 3402 + 42 = 3444
Step 83: 3444 + 42 = 3486
Step 84: 3486 + 42 = 3528
Step 85: 3528 + 42 = 3570
Step 86: 3570 + 42 = 3612
Step 87: 3612 + 42 = 3654
Step 88: 3654 + 42 = 3696
Step 89: 3696 + 42 = 3738
Step 90: 3738 + 42 = 3780
Step 91: 3780 + 42 = 3822
Step 92: 3822 + 42 = 3864
Step 93: 3864 + 42 = 3906
Step 94: 3906 + 42 = 3948
Step 95: 3948 + 42 = 3990
Step 96: 3990 + 42 = 4032
Step 97: 4032 + 42 = 4074
Step 98: 4074 + 42 = 4116
Step 99: 4116 + 42 = 4158
Step 100: 4158 + 42 = 4200
Step 101: 4200 + 42 = 4242
Step 102: 4242 + 42 = 4284
Step 103: 4284 + 42 = 4326
Step 104: 4326 + 42 = 4368
Step 105: 4368 + 42 = 4410
Step 106: 4410 + 42 = 4452
Step 107: 4452 + 42 = 4494
Step 108: 4494 + 42 = 4536
Step 109: 4536 + 42 = 4578
Step 110: 4578 + 42 = 4620
Step 111: 4620 + 42 = 4662
Step 112: 4662 + 42 = 4704
Step 113: 4704 + 42 = 4746
Step 114: 4746 + 42 = 4788
Step 115: 4788 + 42 = 4830
Step 116: 4830 + 42 = 4872
Step 117: 4872 + 42 = 4914
Step 118: 4914 + 42 = 4956
Step 119: 4956 + 42 = 4998
Step 120: 4998 + 42 = 5040
Step 121: 5040 + 42 = 5082
Step 122: 5082 + 42 = 5124
Step 123: 5124 + 42 = 5166
Step 124: 5166 + 42 = 5208
Step 125: 5208 + 42 = 5250
Step 126: 5250 + 42 = 5292
Step 127: 5292 + 42 = 5334
Step 128: 5334 + 42 = 5376
Step 129: 5376 + 42 = 5418
Step 130: 5418 + 42 = 5460
Step 131: 5460 + 42 = 5502
Step 132: 5502 + 42 = 5544
Step 133: 5544 + 42 = 5586
Step 134: 5586 + 42 = 5628
Step 135: 5628 + 42 = 5670
Step 136: 5670 + 42 = 5712
Step 137: 5712 + 42 = 5754
Step 138: 5754 + 42 = 5796
Step 139: 5796 + 42 = 5838
Step 140: 5838 + 42 = 5880
Step 141: 5880 + 42 = 5922
Step 142: 5922 + 42 = 5964
Step 143: 5964 + 42 = 6006
Step 144: 6006 + 42 = 6048
Step 145: 6048 + 42 = 6090
Step 146: 6090 + 42 = 6132
Step 147: 6132 + 42 = 6174
Step 148: 6174 + 42 = 6216
Step 149: 6216 + 42 = 6258
Step 150: 6258 + 42 = 6300
Step 151: 6300 + 42 = 6342
Step 152: 6342 + 42 = 6384
Step 153: 6384 + 42 = 6426
Step 154: 6426 + 42 = 6468
Step 155: 6468 + 42 = 6510
Step 156: 6510 + 42 = 6552
Step 157: 6552 + 42 = 6594
Step 158: 6594 + 42 = 6636
Step 159: 6636 + 42 = 6678
Step 160: 6678 + 42 = 6720
Step 161: 6720 + 42 = 6762
Step 162: 6762 + 42 = 6804
Step 163: 6804 + 42 = 6846
Step 164: 6846 + 42 = 6888
Step 165: 6888 + 42 = 6930
Step 166: 6930 + 42 = 6972
Step 167: 6972 + 42 = 7014
Step 168: 7014 + 42 = 7056
Step 169: 7056 + 42 = 7098
Step 170: 7098 + 42 = 7140
Step 171: 7140 + 42 = 7182
Step 172: 7182 + 42 = 7224
Step 173: 7224 + 42 = 7266
Step 174: 7266 + 42 = 7308
Step 175: 7308 + 42 = 7350
Step 176: 7350 + 42 = 7392
Step 177: 7392 + 42 = 7434
Step 178: 7434 + 42 = 7476
Step 179: 7476 + 42 = 7518
Step 180: 7518 + 42 = 7560
Step 181: 7560 + 42 = 7602
Step 182: 7602 + 42 = 7644
Step 183: 7644 + 42 = 7686
Step 184: 7686 + 42 = 7728
Step 185: 7728 + 42 = 7770
Step 186: 7770 + 42 = 7812
Step 187: 7812 + 42 = 7854
Step 188: 7854 + 42 = 7896
Step 189: 7896 + 42 = 7938
Step 190: 7938 + 42 = 7980
Step 191: 7980 + 42 = 8022
Step 192: 8022 + 42 = 8064
Step 193: 8064 + 42 = 8106
Step 194: 8106 + 42 = 8148
Step 195: 8148 + 42 = 8190
Step 196: 8190 + 42 = 8232
Step 197: 8232 + 42 = 8274
Step 198: 8274 + 42 = 8316
Step 199: 8316 + 42 = 8358
Step 200: 8358 + 42 = 8400
Step 201: 8400 + 42 = 8442
Step 202: 8442 + 42 = 8484
Step 203: 8484 + 42 = 8526
Step 204: 8526 + 42 = 8568
Step 205: 8568 + 42 = 8610
Step 206: 8610 + 42 = 8652
Step 207: 8652 + 42 = 8694
Step 208: 8694 + 42 = 8736
Step 209: 8736 + 42 = 8778
Step 210: 8778 + 42 = 8820
Step 211: 8820 + 42 = 8862
Step 212: 8862 + 42 = 8904
Step 213: 8904 + 42 = 8946
Step 214: 8946 + 42 = 8988
Step 215: 8988 + 42 = 9030
Step 216: 9030 + 42 = 9072
Step 217: 9072 + 42 = 9114
Step 218: 9114 + 42 = 9156
Step 219: 9156 + 42 = 9198
Step 220: 9198 + 42 = 9240
Step 221: 9240 + 42 = 9282
Step 222: 9282 + 42 = 9324
Step 223: 9324 + 42 = 9366
Step 224: 9366 + 42 = 9408
Step 225: 9408 + 42 = 9450
Step 226: 9450 + 42 = 9492
Step 227: 9492 + 42 = 9534
Step 228: 9534 + 42 = 9576
Step 229: 9576 + 42 = 9618
Step 230: 9618 + 42 = 9660
Step 231: 9660 + 42 = 9702
Step 232: 9702 + 42 = 9744
Step 233: 9744 + 42 = 9786
Step 234: 9786 + 42 = 9828
Step 235: 9828 + 42 = 9870
Step 236: 9870 + 42 = 9912
Step 237: 9912 + 42 = 9954
Step 238: 9954 + 42 = 9996
Step 239: 9996 + 42 = 10038
Step 240: 10038 + 42 = 10080
Step 241: 10080 + 42 = 10122
Step 242: 10122 + 42 = 10164
Step 243: 10164 + 42 = 10206
Step 244: 10206 + 42 = 10248
Step 245: 10248 + 42 = 10290
Step 246: 10290 + 42 = 10332
Step 247: 10332 + 42 = 10374
Step 248: 10374 + 42 = 10416

So, 42*248 = 10416