Let's get this math done. We have 820 and we're going to multiply it by 419. This is the same as taking 820 and adding it to itself 419 times.
Step 1: 0 + 820 = 820
Step 2: 820 + 820 = 1640
Step 3: 1640 + 820 = 2460
Step 4: 2460 + 820 = 3280
Step 5: 3280 + 820 = 4100
Step 6: 4100 + 820 = 4920
Step 7: 4920 + 820 = 5740
Step 8: 5740 + 820 = 6560
Step 9: 6560 + 820 = 7380
Step 10: 7380 + 820 = 8200
Step 11: 8200 + 820 = 9020
Step 12: 9020 + 820 = 9840
Step 13: 9840 + 820 = 10660
Step 14: 10660 + 820 = 11480
Step 15: 11480 + 820 = 12300
Step 16: 12300 + 820 = 13120
Step 17: 13120 + 820 = 13940
Step 18: 13940 + 820 = 14760
Step 19: 14760 + 820 = 15580
Step 20: 15580 + 820 = 16400
Step 21: 16400 + 820 = 17220
Step 22: 17220 + 820 = 18040
Step 23: 18040 + 820 = 18860
Step 24: 18860 + 820 = 19680
Step 25: 19680 + 820 = 20500
Step 26: 20500 + 820 = 21320
Step 27: 21320 + 820 = 22140
Step 28: 22140 + 820 = 22960
Step 29: 22960 + 820 = 23780
Step 30: 23780 + 820 = 24600
Step 31: 24600 + 820 = 25420
Step 32: 25420 + 820 = 26240
Step 33: 26240 + 820 = 27060
Step 34: 27060 + 820 = 27880
Step 35: 27880 + 820 = 28700
Step 36: 28700 + 820 = 29520
Step 37: 29520 + 820 = 30340
Step 38: 30340 + 820 = 31160
Step 39: 31160 + 820 = 31980
Step 40: 31980 + 820 = 32800
Step 41: 32800 + 820 = 33620
Step 42: 33620 + 820 = 34440
Step 43: 34440 + 820 = 35260
Step 44: 35260 + 820 = 36080
Step 45: 36080 + 820 = 36900
Step 46: 36900 + 820 = 37720
Step 47: 37720 + 820 = 38540
Step 48: 38540 + 820 = 39360
Step 49: 39360 + 820 = 40180
Step 50: 40180 + 820 = 41000
Step 51: 41000 + 820 = 41820
Step 52: 41820 + 820 = 42640
Step 53: 42640 + 820 = 43460
Step 54: 43460 + 820 = 44280
Step 55: 44280 + 820 = 45100
Step 56: 45100 + 820 = 45920
Step 57: 45920 + 820 = 46740
Step 58: 46740 + 820 = 47560
Step 59: 47560 + 820 = 48380
Step 60: 48380 + 820 = 49200
Step 61: 49200 + 820 = 50020
Step 62: 50020 + 820 = 50840
Step 63: 50840 + 820 = 51660
Step 64: 51660 + 820 = 52480
Step 65: 52480 + 820 = 53300
Step 66: 53300 + 820 = 54120
Step 67: 54120 + 820 = 54940
Step 68: 54940 + 820 = 55760
Step 69: 55760 + 820 = 56580
Step 70: 56580 + 820 = 57400
Step 71: 57400 + 820 = 58220
Step 72: 58220 + 820 = 59040
Step 73: 59040 + 820 = 59860
Step 74: 59860 + 820 = 60680
Step 75: 60680 + 820 = 61500
Step 76: 61500 + 820 = 62320
Step 77: 62320 + 820 = 63140
Step 78: 63140 + 820 = 63960
Step 79: 63960 + 820 = 64780
Step 80: 64780 + 820 = 65600
Step 81: 65600 + 820 = 66420
Step 82: 66420 + 820 = 67240
Step 83: 67240 + 820 = 68060
Step 84: 68060 + 820 = 68880
Step 85: 68880 + 820 = 69700
Step 86: 69700 + 820 = 70520
Step 87: 70520 + 820 = 71340
Step 88: 71340 + 820 = 72160
Step 89: 72160 + 820 = 72980
Step 90: 72980 + 820 = 73800
Step 91: 73800 + 820 = 74620
Step 92: 74620 + 820 = 75440
Step 93: 75440 + 820 = 76260
Step 94: 76260 + 820 = 77080
Step 95: 77080 + 820 = 77900
Step 96: 77900 + 820 = 78720
Step 97: 78720 + 820 = 79540
Step 98: 79540 + 820 = 80360
Step 99: 80360 + 820 = 81180
Step 100: 81180 + 820 = 82000
Step 101: 82000 + 820 = 82820
Step 102: 82820 + 820 = 83640
Step 103: 83640 + 820 = 84460
Step 104: 84460 + 820 = 85280
Step 105: 85280 + 820 = 86100
Step 106: 86100 + 820 = 86920
Step 107: 86920 + 820 = 87740
Step 108: 87740 + 820 = 88560
Step 109: 88560 + 820 = 89380
Step 110: 89380 + 820 = 90200
Step 111: 90200 + 820 = 91020
Step 112: 91020 + 820 = 91840
Step 113: 91840 + 820 = 92660
Step 114: 92660 + 820 = 93480
Step 115: 93480 + 820 = 94300
Step 116: 94300 + 820 = 95120
Step 117: 95120 + 820 = 95940
Step 118: 95940 + 820 = 96760
Step 119: 96760 + 820 = 97580
Step 120: 97580 + 820 = 98400
Step 121: 98400 + 820 = 99220
Step 122: 99220 + 820 = 100040
Step 123: 100040 + 820 = 100860
Step 124: 100860 + 820 = 101680
Step 125: 101680 + 820 = 102500
Step 126: 102500 + 820 = 103320
Step 127: 103320 + 820 = 104140
Step 128: 104140 + 820 = 104960
Step 129: 104960 + 820 = 105780
Step 130: 105780 + 820 = 106600
Step 131: 106600 + 820 = 107420
Step 132: 107420 + 820 = 108240
Step 133: 108240 + 820 = 109060
Step 134: 109060 + 820 = 109880
Step 135: 109880 + 820 = 110700
Step 136: 110700 + 820 = 111520
Step 137: 111520 + 820 = 112340
Step 138: 112340 + 820 = 113160
Step 139: 113160 + 820 = 113980
Step 140: 113980 + 820 = 114800
Step 141: 114800 + 820 = 115620
Step 142: 115620 + 820 = 116440
Step 143: 116440 + 820 = 117260
Step 144: 117260 + 820 = 118080
Step 145: 118080 + 820 = 118900
Step 146: 118900 + 820 = 119720
Step 147: 119720 + 820 = 120540
Step 148: 120540 + 820 = 121360
Step 149: 121360 + 820 = 122180
Step 150: 122180 + 820 = 123000
Step 151: 123000 + 820 = 123820
Step 152: 123820 + 820 = 124640
Step 153: 124640 + 820 = 125460
Step 154: 125460 + 820 = 126280
Step 155: 126280 + 820 = 127100
Step 156: 127100 + 820 = 127920
Step 157: 127920 + 820 = 128740
Step 158: 128740 + 820 = 129560
Step 159: 129560 + 820 = 130380
Step 160: 130380 + 820 = 131200
Step 161: 131200 + 820 = 132020
Step 162: 132020 + 820 = 132840
Step 163: 132840 + 820 = 133660
Step 164: 133660 + 820 = 134480
Step 165: 134480 + 820 = 135300
Step 166: 135300 + 820 = 136120
Step 167: 136120 + 820 = 136940
Step 168: 136940 + 820 = 137760
Step 169: 137760 + 820 = 138580
Step 170: 138580 + 820 = 139400
Step 171: 139400 + 820 = 140220
Step 172: 140220 + 820 = 141040
Step 173: 141040 + 820 = 141860
Step 174: 141860 + 820 = 142680
Step 175: 142680 + 820 = 143500
Step 176: 143500 + 820 = 144320
Step 177: 144320 + 820 = 145140
Step 178: 145140 + 820 = 145960
Step 179: 145960 + 820 = 146780
Step 180: 146780 + 820 = 147600
Step 181: 147600 + 820 = 148420
Step 182: 148420 + 820 = 149240
Step 183: 149240 + 820 = 150060
Step 184: 150060 + 820 = 150880
Step 185: 150880 + 820 = 151700
Step 186: 151700 + 820 = 152520
Step 187: 152520 + 820 = 153340
Step 188: 153340 + 820 = 154160
Step 189: 154160 + 820 = 154980
Step 190: 154980 + 820 = 155800
Step 191: 155800 + 820 = 156620
Step 192: 156620 + 820 = 157440
Step 193: 157440 + 820 = 158260
Step 194: 158260 + 820 = 159080
Step 195: 159080 + 820 = 159900
Step 196: 159900 + 820 = 160720
Step 197: 160720 + 820 = 161540
Step 198: 161540 + 820 = 162360
Step 199: 162360 + 820 = 163180
Step 200: 163180 + 820 = 164000
Step 201: 164000 + 820 = 164820
Step 202: 164820 + 820 = 165640
Step 203: 165640 + 820 = 166460
Step 204: 166460 + 820 = 167280
Step 205: 167280 + 820 = 168100
Step 206: 168100 + 820 = 168920
Step 207: 168920 + 820 = 169740
Step 208: 169740 + 820 = 170560
Step 209: 170560 + 820 = 171380
Step 210: 171380 + 820 = 172200
Step 211: 172200 + 820 = 173020
Step 212: 173020 + 820 = 173840
Step 213: 173840 + 820 = 174660
Step 214: 174660 + 820 = 175480
Step 215: 175480 + 820 = 176300
Step 216: 176300 + 820 = 177120
Step 217: 177120 + 820 = 177940
Step 218: 177940 + 820 = 178760
Step 219: 178760 + 820 = 179580
Step 220: 179580 + 820 = 180400
Step 221: 180400 + 820 = 181220
Step 222: 181220 + 820 = 182040
Step 223: 182040 + 820 = 182860
Step 224: 182860 + 820 = 183680
Step 225: 183680 + 820 = 184500
Step 226: 184500 + 820 = 185320
Step 227: 185320 + 820 = 186140
Step 228: 186140 + 820 = 186960
Step 229: 186960 + 820 = 187780
Step 230: 187780 + 820 = 188600
Step 231: 188600 + 820 = 189420
Step 232: 189420 + 820 = 190240
Step 233: 190240 + 820 = 191060
Step 234: 191060 + 820 = 191880
Step 235: 191880 + 820 = 192700
Step 236: 192700 + 820 = 193520
Step 237: 193520 + 820 = 194340
Step 238: 194340 + 820 = 195160
Step 239: 195160 + 820 = 195980
Step 240: 195980 + 820 = 196800
Step 241: 196800 + 820 = 197620
Step 242: 197620 + 820 = 198440
Step 243: 198440 + 820 = 199260
Step 244: 199260 + 820 = 200080
Step 245: 200080 + 820 = 200900
Step 246: 200900 + 820 = 201720
Step 247: 201720 + 820 = 202540
Step 248: 202540 + 820 = 203360
Step 249: 203360 + 820 = 204180
Step 250: 204180 + 820 = 205000
Step 251: 205000 + 820 = 205820
Step 252: 205820 + 820 = 206640
Step 253: 206640 + 820 = 207460
Step 254: 207460 + 820 = 208280
Step 255: 208280 + 820 = 209100
Step 256: 209100 + 820 = 209920
Step 257: 209920 + 820 = 210740
Step 258: 210740 + 820 = 211560
Step 259: 211560 + 820 = 212380
Step 260: 212380 + 820 = 213200
Step 261: 213200 + 820 = 214020
Step 262: 214020 + 820 = 214840
Step 263: 214840 + 820 = 215660
Step 264: 215660 + 820 = 216480
Step 265: 216480 + 820 = 217300
Step 266: 217300 + 820 = 218120
Step 267: 218120 + 820 = 218940
Step 268: 218940 + 820 = 219760
Step 269: 219760 + 820 = 220580
Step 270: 220580 + 820 = 221400
Step 271: 221400 + 820 = 222220
Step 272: 222220 + 820 = 223040
Step 273: 223040 + 820 = 223860
Step 274: 223860 + 820 = 224680
Step 275: 224680 + 820 = 225500
Step 276: 225500 + 820 = 226320
Step 277: 226320 + 820 = 227140
Step 278: 227140 + 820 = 227960
Step 279: 227960 + 820 = 228780
Step 280: 228780 + 820 = 229600
Step 281: 229600 + 820 = 230420
Step 282: 230420 + 820 = 231240
Step 283: 231240 + 820 = 232060
Step 284: 232060 + 820 = 232880
Step 285: 232880 + 820 = 233700
Step 286: 233700 + 820 = 234520
Step 287: 234520 + 820 = 235340
Step 288: 235340 + 820 = 236160
Step 289: 236160 + 820 = 236980
Step 290: 236980 + 820 = 237800
Step 291: 237800 + 820 = 238620
Step 292: 238620 + 820 = 239440
Step 293: 239440 + 820 = 240260
Step 294: 240260 + 820 = 241080
Step 295: 241080 + 820 = 241900
Step 296: 241900 + 820 = 242720
Step 297: 242720 + 820 = 243540
Step 298: 243540 + 820 = 244360
Step 299: 244360 + 820 = 245180
Step 300: 245180 + 820 = 246000
Step 301: 246000 + 820 = 246820
Step 302: 246820 + 820 = 247640
Step 303: 247640 + 820 = 248460
Step 304: 248460 + 820 = 249280
Step 305: 249280 + 820 = 250100
Step 306: 250100 + 820 = 250920
Step 307: 250920 + 820 = 251740
Step 308: 251740 + 820 = 252560
Step 309: 252560 + 820 = 253380
Step 310: 253380 + 820 = 254200
Step 311: 254200 + 820 = 255020
Step 312: 255020 + 820 = 255840
Step 313: 255840 + 820 = 256660
Step 314: 256660 + 820 = 257480
Step 315: 257480 + 820 = 258300
Step 316: 258300 + 820 = 259120
Step 317: 259120 + 820 = 259940
Step 318: 259940 + 820 = 260760
Step 319: 260760 + 820 = 261580
Step 320: 261580 + 820 = 262400
Step 321: 262400 + 820 = 263220
Step 322: 263220 + 820 = 264040
Step 323: 264040 + 820 = 264860
Step 324: 264860 + 820 = 265680
Step 325: 265680 + 820 = 266500
Step 326: 266500 + 820 = 267320
Step 327: 267320 + 820 = 268140
Step 328: 268140 + 820 = 268960
Step 329: 268960 + 820 = 269780
Step 330: 269780 + 820 = 270600
Step 331: 270600 + 820 = 271420
Step 332: 271420 + 820 = 272240
Step 333: 272240 + 820 = 273060
Step 334: 273060 + 820 = 273880
Step 335: 273880 + 820 = 274700
Step 336: 274700 + 820 = 275520
Step 337: 275520 + 820 = 276340
Step 338: 276340 + 820 = 277160
Step 339: 277160 + 820 = 277980
Step 340: 277980 + 820 = 278800
Step 341: 278800 + 820 = 279620
Step 342: 279620 + 820 = 280440
Step 343: 280440 + 820 = 281260
Step 344: 281260 + 820 = 282080
Step 345: 282080 + 820 = 282900
Step 346: 282900 + 820 = 283720
Step 347: 283720 + 820 = 284540
Step 348: 284540 + 820 = 285360
Step 349: 285360 + 820 = 286180
Step 350: 286180 + 820 = 287000
Step 351: 287000 + 820 = 287820
Step 352: 287820 + 820 = 288640
Step 353: 288640 + 820 = 289460
Step 354: 289460 + 820 = 290280
Step 355: 290280 + 820 = 291100
Step 356: 291100 + 820 = 291920
Step 357: 291920 + 820 = 292740
Step 358: 292740 + 820 = 293560
Step 359: 293560 + 820 = 294380
Step 360: 294380 + 820 = 295200
Step 361: 295200 + 820 = 296020
Step 362: 296020 + 820 = 296840
Step 363: 296840 + 820 = 297660
Step 364: 297660 + 820 = 298480
Step 365: 298480 + 820 = 299300
Step 366: 299300 + 820 = 300120
Step 367: 300120 + 820 = 300940
Step 368: 300940 + 820 = 301760
Step 369: 301760 + 820 = 302580
Step 370: 302580 + 820 = 303400
Step 371: 303400 + 820 = 304220
Step 372: 304220 + 820 = 305040
Step 373: 305040 + 820 = 305860
Step 374: 305860 + 820 = 306680
Step 375: 306680 + 820 = 307500
Step 376: 307500 + 820 = 308320
Step 377: 308320 + 820 = 309140
Step 378: 309140 + 820 = 309960
Step 379: 309960 + 820 = 310780
Step 380: 310780 + 820 = 311600
Step 381: 311600 + 820 = 312420
Step 382: 312420 + 820 = 313240
Step 383: 313240 + 820 = 314060
Step 384: 314060 + 820 = 314880
Step 385: 314880 + 820 = 315700
Step 386: 315700 + 820 = 316520
Step 387: 316520 + 820 = 317340
Step 388: 317340 + 820 = 318160
Step 389: 318160 + 820 = 318980
Step 390: 318980 + 820 = 319800
Step 391: 319800 + 820 = 320620
Step 392: 320620 + 820 = 321440
Step 393: 321440 + 820 = 322260
Step 394: 322260 + 820 = 323080
Step 395: 323080 + 820 = 323900
Step 396: 323900 + 820 = 324720
Step 397: 324720 + 820 = 325540
Step 398: 325540 + 820 = 326360
Step 399: 326360 + 820 = 327180
Step 400: 327180 + 820 = 328000
Step 401: 328000 + 820 = 328820
Step 402: 328820 + 820 = 329640
Step 403: 329640 + 820 = 330460
Step 404: 330460 + 820 = 331280
Step 405: 331280 + 820 = 332100
Step 406: 332100 + 820 = 332920
Step 407: 332920 + 820 = 333740
Step 408: 333740 + 820 = 334560
Step 409: 334560 + 820 = 335380
Step 410: 335380 + 820 = 336200
Step 411: 336200 + 820 = 337020
Step 412: 337020 + 820 = 337840
Step 413: 337840 + 820 = 338660
Step 414: 338660 + 820 = 339480
Step 415: 339480 + 820 = 340300
Step 416: 340300 + 820 = 341120
Step 417: 341120 + 820 = 341940
Step 418: 341940 + 820 = 342760
Step 419: 342760 + 820 = 343580

So, 820*419 = 343580