Sure thing! We've got 105 and we're gonna multiply it by 402. That's the same as adding 105 to itself 402 times.
Step 1: 0 + 105 = 105
Step 2: 105 + 105 = 210
Step 3: 210 + 105 = 315
Step 4: 315 + 105 = 420
Step 5: 420 + 105 = 525
Step 6: 525 + 105 = 630
Step 7: 630 + 105 = 735
Step 8: 735 + 105 = 840
Step 9: 840 + 105 = 945
Step 10: 945 + 105 = 1050
Step 11: 1050 + 105 = 1155
Step 12: 1155 + 105 = 1260
Step 13: 1260 + 105 = 1365
Step 14: 1365 + 105 = 1470
Step 15: 1470 + 105 = 1575
Step 16: 1575 + 105 = 1680
Step 17: 1680 + 105 = 1785
Step 18: 1785 + 105 = 1890
Step 19: 1890 + 105 = 1995
Step 20: 1995 + 105 = 2100
Step 21: 2100 + 105 = 2205
Step 22: 2205 + 105 = 2310
Step 23: 2310 + 105 = 2415
Step 24: 2415 + 105 = 2520
Step 25: 2520 + 105 = 2625
Step 26: 2625 + 105 = 2730
Step 27: 2730 + 105 = 2835
Step 28: 2835 + 105 = 2940
Step 29: 2940 + 105 = 3045
Step 30: 3045 + 105 = 3150
Step 31: 3150 + 105 = 3255
Step 32: 3255 + 105 = 3360
Step 33: 3360 + 105 = 3465
Step 34: 3465 + 105 = 3570
Step 35: 3570 + 105 = 3675
Step 36: 3675 + 105 = 3780
Step 37: 3780 + 105 = 3885
Step 38: 3885 + 105 = 3990
Step 39: 3990 + 105 = 4095
Step 40: 4095 + 105 = 4200
Step 41: 4200 + 105 = 4305
Step 42: 4305 + 105 = 4410
Step 43: 4410 + 105 = 4515
Step 44: 4515 + 105 = 4620
Step 45: 4620 + 105 = 4725
Step 46: 4725 + 105 = 4830
Step 47: 4830 + 105 = 4935
Step 48: 4935 + 105 = 5040
Step 49: 5040 + 105 = 5145
Step 50: 5145 + 105 = 5250
Step 51: 5250 + 105 = 5355
Step 52: 5355 + 105 = 5460
Step 53: 5460 + 105 = 5565
Step 54: 5565 + 105 = 5670
Step 55: 5670 + 105 = 5775
Step 56: 5775 + 105 = 5880
Step 57: 5880 + 105 = 5985
Step 58: 5985 + 105 = 6090
Step 59: 6090 + 105 = 6195
Step 60: 6195 + 105 = 6300
Step 61: 6300 + 105 = 6405
Step 62: 6405 + 105 = 6510
Step 63: 6510 + 105 = 6615
Step 64: 6615 + 105 = 6720
Step 65: 6720 + 105 = 6825
Step 66: 6825 + 105 = 6930
Step 67: 6930 + 105 = 7035
Step 68: 7035 + 105 = 7140
Step 69: 7140 + 105 = 7245
Step 70: 7245 + 105 = 7350
Step 71: 7350 + 105 = 7455
Step 72: 7455 + 105 = 7560
Step 73: 7560 + 105 = 7665
Step 74: 7665 + 105 = 7770
Step 75: 7770 + 105 = 7875
Step 76: 7875 + 105 = 7980
Step 77: 7980 + 105 = 8085
Step 78: 8085 + 105 = 8190
Step 79: 8190 + 105 = 8295
Step 80: 8295 + 105 = 8400
Step 81: 8400 + 105 = 8505
Step 82: 8505 + 105 = 8610
Step 83: 8610 + 105 = 8715
Step 84: 8715 + 105 = 8820
Step 85: 8820 + 105 = 8925
Step 86: 8925 + 105 = 9030
Step 87: 9030 + 105 = 9135
Step 88: 9135 + 105 = 9240
Step 89: 9240 + 105 = 9345
Step 90: 9345 + 105 = 9450
Step 91: 9450 + 105 = 9555
Step 92: 9555 + 105 = 9660
Step 93: 9660 + 105 = 9765
Step 94: 9765 + 105 = 9870
Step 95: 9870 + 105 = 9975
Step 96: 9975 + 105 = 10080
Step 97: 10080 + 105 = 10185
Step 98: 10185 + 105 = 10290
Step 99: 10290 + 105 = 10395
Step 100: 10395 + 105 = 10500
Step 101: 10500 + 105 = 10605
Step 102: 10605 + 105 = 10710
Step 103: 10710 + 105 = 10815
Step 104: 10815 + 105 = 10920
Step 105: 10920 + 105 = 11025
Step 106: 11025 + 105 = 11130
Step 107: 11130 + 105 = 11235
Step 108: 11235 + 105 = 11340
Step 109: 11340 + 105 = 11445
Step 110: 11445 + 105 = 11550
Step 111: 11550 + 105 = 11655
Step 112: 11655 + 105 = 11760
Step 113: 11760 + 105 = 11865
Step 114: 11865 + 105 = 11970
Step 115: 11970 + 105 = 12075
Step 116: 12075 + 105 = 12180
Step 117: 12180 + 105 = 12285
Step 118: 12285 + 105 = 12390
Step 119: 12390 + 105 = 12495
Step 120: 12495 + 105 = 12600
Step 121: 12600 + 105 = 12705
Step 122: 12705 + 105 = 12810
Step 123: 12810 + 105 = 12915
Step 124: 12915 + 105 = 13020
Step 125: 13020 + 105 = 13125
Step 126: 13125 + 105 = 13230
Step 127: 13230 + 105 = 13335
Step 128: 13335 + 105 = 13440
Step 129: 13440 + 105 = 13545
Step 130: 13545 + 105 = 13650
Step 131: 13650 + 105 = 13755
Step 132: 13755 + 105 = 13860
Step 133: 13860 + 105 = 13965
Step 134: 13965 + 105 = 14070
Step 135: 14070 + 105 = 14175
Step 136: 14175 + 105 = 14280
Step 137: 14280 + 105 = 14385
Step 138: 14385 + 105 = 14490
Step 139: 14490 + 105 = 14595
Step 140: 14595 + 105 = 14700
Step 141: 14700 + 105 = 14805
Step 142: 14805 + 105 = 14910
Step 143: 14910 + 105 = 15015
Step 144: 15015 + 105 = 15120
Step 145: 15120 + 105 = 15225
Step 146: 15225 + 105 = 15330
Step 147: 15330 + 105 = 15435
Step 148: 15435 + 105 = 15540
Step 149: 15540 + 105 = 15645
Step 150: 15645 + 105 = 15750
Step 151: 15750 + 105 = 15855
Step 152: 15855 + 105 = 15960
Step 153: 15960 + 105 = 16065
Step 154: 16065 + 105 = 16170
Step 155: 16170 + 105 = 16275
Step 156: 16275 + 105 = 16380
Step 157: 16380 + 105 = 16485
Step 158: 16485 + 105 = 16590
Step 159: 16590 + 105 = 16695
Step 160: 16695 + 105 = 16800
Step 161: 16800 + 105 = 16905
Step 162: 16905 + 105 = 17010
Step 163: 17010 + 105 = 17115
Step 164: 17115 + 105 = 17220
Step 165: 17220 + 105 = 17325
Step 166: 17325 + 105 = 17430
Step 167: 17430 + 105 = 17535
Step 168: 17535 + 105 = 17640
Step 169: 17640 + 105 = 17745
Step 170: 17745 + 105 = 17850
Step 171: 17850 + 105 = 17955
Step 172: 17955 + 105 = 18060
Step 173: 18060 + 105 = 18165
Step 174: 18165 + 105 = 18270
Step 175: 18270 + 105 = 18375
Step 176: 18375 + 105 = 18480
Step 177: 18480 + 105 = 18585
Step 178: 18585 + 105 = 18690
Step 179: 18690 + 105 = 18795
Step 180: 18795 + 105 = 18900
Step 181: 18900 + 105 = 19005
Step 182: 19005 + 105 = 19110
Step 183: 19110 + 105 = 19215
Step 184: 19215 + 105 = 19320
Step 185: 19320 + 105 = 19425
Step 186: 19425 + 105 = 19530
Step 187: 19530 + 105 = 19635
Step 188: 19635 + 105 = 19740
Step 189: 19740 + 105 = 19845
Step 190: 19845 + 105 = 19950
Step 191: 19950 + 105 = 20055
Step 192: 20055 + 105 = 20160
Step 193: 20160 + 105 = 20265
Step 194: 20265 + 105 = 20370
Step 195: 20370 + 105 = 20475
Step 196: 20475 + 105 = 20580
Step 197: 20580 + 105 = 20685
Step 198: 20685 + 105 = 20790
Step 199: 20790 + 105 = 20895
Step 200: 20895 + 105 = 21000
Step 201: 21000 + 105 = 21105
Step 202: 21105 + 105 = 21210
Step 203: 21210 + 105 = 21315
Step 204: 21315 + 105 = 21420
Step 205: 21420 + 105 = 21525
Step 206: 21525 + 105 = 21630
Step 207: 21630 + 105 = 21735
Step 208: 21735 + 105 = 21840
Step 209: 21840 + 105 = 21945
Step 210: 21945 + 105 = 22050
Step 211: 22050 + 105 = 22155
Step 212: 22155 + 105 = 22260
Step 213: 22260 + 105 = 22365
Step 214: 22365 + 105 = 22470
Step 215: 22470 + 105 = 22575
Step 216: 22575 + 105 = 22680
Step 217: 22680 + 105 = 22785
Step 218: 22785 + 105 = 22890
Step 219: 22890 + 105 = 22995
Step 220: 22995 + 105 = 23100
Step 221: 23100 + 105 = 23205
Step 222: 23205 + 105 = 23310
Step 223: 23310 + 105 = 23415
Step 224: 23415 + 105 = 23520
Step 225: 23520 + 105 = 23625
Step 226: 23625 + 105 = 23730
Step 227: 23730 + 105 = 23835
Step 228: 23835 + 105 = 23940
Step 229: 23940 + 105 = 24045
Step 230: 24045 + 105 = 24150
Step 231: 24150 + 105 = 24255
Step 232: 24255 + 105 = 24360
Step 233: 24360 + 105 = 24465
Step 234: 24465 + 105 = 24570
Step 235: 24570 + 105 = 24675
Step 236: 24675 + 105 = 24780
Step 237: 24780 + 105 = 24885
Step 238: 24885 + 105 = 24990
Step 239: 24990 + 105 = 25095
Step 240: 25095 + 105 = 25200
Step 241: 25200 + 105 = 25305
Step 242: 25305 + 105 = 25410
Step 243: 25410 + 105 = 25515
Step 244: 25515 + 105 = 25620
Step 245: 25620 + 105 = 25725
Step 246: 25725 + 105 = 25830
Step 247: 25830 + 105 = 25935
Step 248: 25935 + 105 = 26040
Step 249: 26040 + 105 = 26145
Step 250: 26145 + 105 = 26250
Step 251: 26250 + 105 = 26355
Step 252: 26355 + 105 = 26460
Step 253: 26460 + 105 = 26565
Step 254: 26565 + 105 = 26670
Step 255: 26670 + 105 = 26775
Step 256: 26775 + 105 = 26880
Step 257: 26880 + 105 = 26985
Step 258: 26985 + 105 = 27090
Step 259: 27090 + 105 = 27195
Step 260: 27195 + 105 = 27300
Step 261: 27300 + 105 = 27405
Step 262: 27405 + 105 = 27510
Step 263: 27510 + 105 = 27615
Step 264: 27615 + 105 = 27720
Step 265: 27720 + 105 = 27825
Step 266: 27825 + 105 = 27930
Step 267: 27930 + 105 = 28035
Step 268: 28035 + 105 = 28140
Step 269: 28140 + 105 = 28245
Step 270: 28245 + 105 = 28350
Step 271: 28350 + 105 = 28455
Step 272: 28455 + 105 = 28560
Step 273: 28560 + 105 = 28665
Step 274: 28665 + 105 = 28770
Step 275: 28770 + 105 = 28875
Step 276: 28875 + 105 = 28980
Step 277: 28980 + 105 = 29085
Step 278: 29085 + 105 = 29190
Step 279: 29190 + 105 = 29295
Step 280: 29295 + 105 = 29400
Step 281: 29400 + 105 = 29505
Step 282: 29505 + 105 = 29610
Step 283: 29610 + 105 = 29715
Step 284: 29715 + 105 = 29820
Step 285: 29820 + 105 = 29925
Step 286: 29925 + 105 = 30030
Step 287: 30030 + 105 = 30135
Step 288: 30135 + 105 = 30240
Step 289: 30240 + 105 = 30345
Step 290: 30345 + 105 = 30450
Step 291: 30450 + 105 = 30555
Step 292: 30555 + 105 = 30660
Step 293: 30660 + 105 = 30765
Step 294: 30765 + 105 = 30870
Step 295: 30870 + 105 = 30975
Step 296: 30975 + 105 = 31080
Step 297: 31080 + 105 = 31185
Step 298: 31185 + 105 = 31290
Step 299: 31290 + 105 = 31395
Step 300: 31395 + 105 = 31500
Step 301: 31500 + 105 = 31605
Step 302: 31605 + 105 = 31710
Step 303: 31710 + 105 = 31815
Step 304: 31815 + 105 = 31920
Step 305: 31920 + 105 = 32025
Step 306: 32025 + 105 = 32130
Step 307: 32130 + 105 = 32235
Step 308: 32235 + 105 = 32340
Step 309: 32340 + 105 = 32445
Step 310: 32445 + 105 = 32550
Step 311: 32550 + 105 = 32655
Step 312: 32655 + 105 = 32760
Step 313: 32760 + 105 = 32865
Step 314: 32865 + 105 = 32970
Step 315: 32970 + 105 = 33075
Step 316: 33075 + 105 = 33180
Step 317: 33180 + 105 = 33285
Step 318: 33285 + 105 = 33390
Step 319: 33390 + 105 = 33495
Step 320: 33495 + 105 = 33600
Step 321: 33600 + 105 = 33705
Step 322: 33705 + 105 = 33810
Step 323: 33810 + 105 = 33915
Step 324: 33915 + 105 = 34020
Step 325: 34020 + 105 = 34125
Step 326: 34125 + 105 = 34230
Step 327: 34230 + 105 = 34335
Step 328: 34335 + 105 = 34440
Step 329: 34440 + 105 = 34545
Step 330: 34545 + 105 = 34650
Step 331: 34650 + 105 = 34755
Step 332: 34755 + 105 = 34860
Step 333: 34860 + 105 = 34965
Step 334: 34965 + 105 = 35070
Step 335: 35070 + 105 = 35175
Step 336: 35175 + 105 = 35280
Step 337: 35280 + 105 = 35385
Step 338: 35385 + 105 = 35490
Step 339: 35490 + 105 = 35595
Step 340: 35595 + 105 = 35700
Step 341: 35700 + 105 = 35805
Step 342: 35805 + 105 = 35910
Step 343: 35910 + 105 = 36015
Step 344: 36015 + 105 = 36120
Step 345: 36120 + 105 = 36225
Step 346: 36225 + 105 = 36330
Step 347: 36330 + 105 = 36435
Step 348: 36435 + 105 = 36540
Step 349: 36540 + 105 = 36645
Step 350: 36645 + 105 = 36750
Step 351: 36750 + 105 = 36855
Step 352: 36855 + 105 = 36960
Step 353: 36960 + 105 = 37065
Step 354: 37065 + 105 = 37170
Step 355: 37170 + 105 = 37275
Step 356: 37275 + 105 = 37380
Step 357: 37380 + 105 = 37485
Step 358: 37485 + 105 = 37590
Step 359: 37590 + 105 = 37695
Step 360: 37695 + 105 = 37800
Step 361: 37800 + 105 = 37905
Step 362: 37905 + 105 = 38010
Step 363: 38010 + 105 = 38115
Step 364: 38115 + 105 = 38220
Step 365: 38220 + 105 = 38325
Step 366: 38325 + 105 = 38430
Step 367: 38430 + 105 = 38535
Step 368: 38535 + 105 = 38640
Step 369: 38640 + 105 = 38745
Step 370: 38745 + 105 = 38850
Step 371: 38850 + 105 = 38955
Step 372: 38955 + 105 = 39060
Step 373: 39060 + 105 = 39165
Step 374: 39165 + 105 = 39270
Step 375: 39270 + 105 = 39375
Step 376: 39375 + 105 = 39480
Step 377: 39480 + 105 = 39585
Step 378: 39585 + 105 = 39690
Step 379: 39690 + 105 = 39795
Step 380: 39795 + 105 = 39900
Step 381: 39900 + 105 = 40005
Step 382: 40005 + 105 = 40110
Step 383: 40110 + 105 = 40215
Step 384: 40215 + 105 = 40320
Step 385: 40320 + 105 = 40425
Step 386: 40425 + 105 = 40530
Step 387: 40530 + 105 = 40635
Step 388: 40635 + 105 = 40740
Step 389: 40740 + 105 = 40845
Step 390: 40845 + 105 = 40950
Step 391: 40950 + 105 = 41055
Step 392: 41055 + 105 = 41160
Step 393: 41160 + 105 = 41265
Step 394: 41265 + 105 = 41370
Step 395: 41370 + 105 = 41475
Step 396: 41475 + 105 = 41580
Step 397: 41580 + 105 = 41685
Step 398: 41685 + 105 = 41790
Step 399: 41790 + 105 = 41895
Step 400: 41895 + 105 = 42000
Step 401: 42000 + 105 = 42105
Step 402: 42105 + 105 = 42210

So, 105*402 = 42210