Alright, let's solve this math problem step by step. First, we have the number 870. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 394. So, we're going to take the number 870 and add it to itself 394 times.
Step 1: 0 + 870 = 870
Step 2: 870 + 870 = 1740
Step 3: 1740 + 870 = 2610
Step 4: 2610 + 870 = 3480
Step 5: 3480 + 870 = 4350
Step 6: 4350 + 870 = 5220
Step 7: 5220 + 870 = 6090
Step 8: 6090 + 870 = 6960
Step 9: 6960 + 870 = 7830
Step 10: 7830 + 870 = 8700
Step 11: 8700 + 870 = 9570
Step 12: 9570 + 870 = 10440
Step 13: 10440 + 870 = 11310
Step 14: 11310 + 870 = 12180
Step 15: 12180 + 870 = 13050
Step 16: 13050 + 870 = 13920
Step 17: 13920 + 870 = 14790
Step 18: 14790 + 870 = 15660
Step 19: 15660 + 870 = 16530
Step 20: 16530 + 870 = 17400
Step 21: 17400 + 870 = 18270
Step 22: 18270 + 870 = 19140
Step 23: 19140 + 870 = 20010
Step 24: 20010 + 870 = 20880
Step 25: 20880 + 870 = 21750
Step 26: 21750 + 870 = 22620
Step 27: 22620 + 870 = 23490
Step 28: 23490 + 870 = 24360
Step 29: 24360 + 870 = 25230
Step 30: 25230 + 870 = 26100
Step 31: 26100 + 870 = 26970
Step 32: 26970 + 870 = 27840
Step 33: 27840 + 870 = 28710
Step 34: 28710 + 870 = 29580
Step 35: 29580 + 870 = 30450
Step 36: 30450 + 870 = 31320
Step 37: 31320 + 870 = 32190
Step 38: 32190 + 870 = 33060
Step 39: 33060 + 870 = 33930
Step 40: 33930 + 870 = 34800
Step 41: 34800 + 870 = 35670
Step 42: 35670 + 870 = 36540
Step 43: 36540 + 870 = 37410
Step 44: 37410 + 870 = 38280
Step 45: 38280 + 870 = 39150
Step 46: 39150 + 870 = 40020
Step 47: 40020 + 870 = 40890
Step 48: 40890 + 870 = 41760
Step 49: 41760 + 870 = 42630
Step 50: 42630 + 870 = 43500
Step 51: 43500 + 870 = 44370
Step 52: 44370 + 870 = 45240
Step 53: 45240 + 870 = 46110
Step 54: 46110 + 870 = 46980
Step 55: 46980 + 870 = 47850
Step 56: 47850 + 870 = 48720
Step 57: 48720 + 870 = 49590
Step 58: 49590 + 870 = 50460
Step 59: 50460 + 870 = 51330
Step 60: 51330 + 870 = 52200
Step 61: 52200 + 870 = 53070
Step 62: 53070 + 870 = 53940
Step 63: 53940 + 870 = 54810
Step 64: 54810 + 870 = 55680
Step 65: 55680 + 870 = 56550
Step 66: 56550 + 870 = 57420
Step 67: 57420 + 870 = 58290
Step 68: 58290 + 870 = 59160
Step 69: 59160 + 870 = 60030
Step 70: 60030 + 870 = 60900
Step 71: 60900 + 870 = 61770
Step 72: 61770 + 870 = 62640
Step 73: 62640 + 870 = 63510
Step 74: 63510 + 870 = 64380
Step 75: 64380 + 870 = 65250
Step 76: 65250 + 870 = 66120
Step 77: 66120 + 870 = 66990
Step 78: 66990 + 870 = 67860
Step 79: 67860 + 870 = 68730
Step 80: 68730 + 870 = 69600
Step 81: 69600 + 870 = 70470
Step 82: 70470 + 870 = 71340
Step 83: 71340 + 870 = 72210
Step 84: 72210 + 870 = 73080
Step 85: 73080 + 870 = 73950
Step 86: 73950 + 870 = 74820
Step 87: 74820 + 870 = 75690
Step 88: 75690 + 870 = 76560
Step 89: 76560 + 870 = 77430
Step 90: 77430 + 870 = 78300
Step 91: 78300 + 870 = 79170
Step 92: 79170 + 870 = 80040
Step 93: 80040 + 870 = 80910
Step 94: 80910 + 870 = 81780
Step 95: 81780 + 870 = 82650
Step 96: 82650 + 870 = 83520
Step 97: 83520 + 870 = 84390
Step 98: 84390 + 870 = 85260
Step 99: 85260 + 870 = 86130
Step 100: 86130 + 870 = 87000
Step 101: 87000 + 870 = 87870
Step 102: 87870 + 870 = 88740
Step 103: 88740 + 870 = 89610
Step 104: 89610 + 870 = 90480
Step 105: 90480 + 870 = 91350
Step 106: 91350 + 870 = 92220
Step 107: 92220 + 870 = 93090
Step 108: 93090 + 870 = 93960
Step 109: 93960 + 870 = 94830
Step 110: 94830 + 870 = 95700
Step 111: 95700 + 870 = 96570
Step 112: 96570 + 870 = 97440
Step 113: 97440 + 870 = 98310
Step 114: 98310 + 870 = 99180
Step 115: 99180 + 870 = 100050
Step 116: 100050 + 870 = 100920
Step 117: 100920 + 870 = 101790
Step 118: 101790 + 870 = 102660
Step 119: 102660 + 870 = 103530
Step 120: 103530 + 870 = 104400
Step 121: 104400 + 870 = 105270
Step 122: 105270 + 870 = 106140
Step 123: 106140 + 870 = 107010
Step 124: 107010 + 870 = 107880
Step 125: 107880 + 870 = 108750
Step 126: 108750 + 870 = 109620
Step 127: 109620 + 870 = 110490
Step 128: 110490 + 870 = 111360
Step 129: 111360 + 870 = 112230
Step 130: 112230 + 870 = 113100
Step 131: 113100 + 870 = 113970
Step 132: 113970 + 870 = 114840
Step 133: 114840 + 870 = 115710
Step 134: 115710 + 870 = 116580
Step 135: 116580 + 870 = 117450
Step 136: 117450 + 870 = 118320
Step 137: 118320 + 870 = 119190
Step 138: 119190 + 870 = 120060
Step 139: 120060 + 870 = 120930
Step 140: 120930 + 870 = 121800
Step 141: 121800 + 870 = 122670
Step 142: 122670 + 870 = 123540
Step 143: 123540 + 870 = 124410
Step 144: 124410 + 870 = 125280
Step 145: 125280 + 870 = 126150
Step 146: 126150 + 870 = 127020
Step 147: 127020 + 870 = 127890
Step 148: 127890 + 870 = 128760
Step 149: 128760 + 870 = 129630
Step 150: 129630 + 870 = 130500
Step 151: 130500 + 870 = 131370
Step 152: 131370 + 870 = 132240
Step 153: 132240 + 870 = 133110
Step 154: 133110 + 870 = 133980
Step 155: 133980 + 870 = 134850
Step 156: 134850 + 870 = 135720
Step 157: 135720 + 870 = 136590
Step 158: 136590 + 870 = 137460
Step 159: 137460 + 870 = 138330
Step 160: 138330 + 870 = 139200
Step 161: 139200 + 870 = 140070
Step 162: 140070 + 870 = 140940
Step 163: 140940 + 870 = 141810
Step 164: 141810 + 870 = 142680
Step 165: 142680 + 870 = 143550
Step 166: 143550 + 870 = 144420
Step 167: 144420 + 870 = 145290
Step 168: 145290 + 870 = 146160
Step 169: 146160 + 870 = 147030
Step 170: 147030 + 870 = 147900
Step 171: 147900 + 870 = 148770
Step 172: 148770 + 870 = 149640
Step 173: 149640 + 870 = 150510
Step 174: 150510 + 870 = 151380
Step 175: 151380 + 870 = 152250
Step 176: 152250 + 870 = 153120
Step 177: 153120 + 870 = 153990
Step 178: 153990 + 870 = 154860
Step 179: 154860 + 870 = 155730
Step 180: 155730 + 870 = 156600
Step 181: 156600 + 870 = 157470
Step 182: 157470 + 870 = 158340
Step 183: 158340 + 870 = 159210
Step 184: 159210 + 870 = 160080
Step 185: 160080 + 870 = 160950
Step 186: 160950 + 870 = 161820
Step 187: 161820 + 870 = 162690
Step 188: 162690 + 870 = 163560
Step 189: 163560 + 870 = 164430
Step 190: 164430 + 870 = 165300
Step 191: 165300 + 870 = 166170
Step 192: 166170 + 870 = 167040
Step 193: 167040 + 870 = 167910
Step 194: 167910 + 870 = 168780
Step 195: 168780 + 870 = 169650
Step 196: 169650 + 870 = 170520
Step 197: 170520 + 870 = 171390
Step 198: 171390 + 870 = 172260
Step 199: 172260 + 870 = 173130
Step 200: 173130 + 870 = 174000
Step 201: 174000 + 870 = 174870
Step 202: 174870 + 870 = 175740
Step 203: 175740 + 870 = 176610
Step 204: 176610 + 870 = 177480
Step 205: 177480 + 870 = 178350
Step 206: 178350 + 870 = 179220
Step 207: 179220 + 870 = 180090
Step 208: 180090 + 870 = 180960
Step 209: 180960 + 870 = 181830
Step 210: 181830 + 870 = 182700
Step 211: 182700 + 870 = 183570
Step 212: 183570 + 870 = 184440
Step 213: 184440 + 870 = 185310
Step 214: 185310 + 870 = 186180
Step 215: 186180 + 870 = 187050
Step 216: 187050 + 870 = 187920
Step 217: 187920 + 870 = 188790
Step 218: 188790 + 870 = 189660
Step 219: 189660 + 870 = 190530
Step 220: 190530 + 870 = 191400
Step 221: 191400 + 870 = 192270
Step 222: 192270 + 870 = 193140
Step 223: 193140 + 870 = 194010
Step 224: 194010 + 870 = 194880
Step 225: 194880 + 870 = 195750
Step 226: 195750 + 870 = 196620
Step 227: 196620 + 870 = 197490
Step 228: 197490 + 870 = 198360
Step 229: 198360 + 870 = 199230
Step 230: 199230 + 870 = 200100
Step 231: 200100 + 870 = 200970
Step 232: 200970 + 870 = 201840
Step 233: 201840 + 870 = 202710
Step 234: 202710 + 870 = 203580
Step 235: 203580 + 870 = 204450
Step 236: 204450 + 870 = 205320
Step 237: 205320 + 870 = 206190
Step 238: 206190 + 870 = 207060
Step 239: 207060 + 870 = 207930
Step 240: 207930 + 870 = 208800
Step 241: 208800 + 870 = 209670
Step 242: 209670 + 870 = 210540
Step 243: 210540 + 870 = 211410
Step 244: 211410 + 870 = 212280
Step 245: 212280 + 870 = 213150
Step 246: 213150 + 870 = 214020
Step 247: 214020 + 870 = 214890
Step 248: 214890 + 870 = 215760
Step 249: 215760 + 870 = 216630
Step 250: 216630 + 870 = 217500
Step 251: 217500 + 870 = 218370
Step 252: 218370 + 870 = 219240
Step 253: 219240 + 870 = 220110
Step 254: 220110 + 870 = 220980
Step 255: 220980 + 870 = 221850
Step 256: 221850 + 870 = 222720
Step 257: 222720 + 870 = 223590
Step 258: 223590 + 870 = 224460
Step 259: 224460 + 870 = 225330
Step 260: 225330 + 870 = 226200
Step 261: 226200 + 870 = 227070
Step 262: 227070 + 870 = 227940
Step 263: 227940 + 870 = 228810
Step 264: 228810 + 870 = 229680
Step 265: 229680 + 870 = 230550
Step 266: 230550 + 870 = 231420
Step 267: 231420 + 870 = 232290
Step 268: 232290 + 870 = 233160
Step 269: 233160 + 870 = 234030
Step 270: 234030 + 870 = 234900
Step 271: 234900 + 870 = 235770
Step 272: 235770 + 870 = 236640
Step 273: 236640 + 870 = 237510
Step 274: 237510 + 870 = 238380
Step 275: 238380 + 870 = 239250
Step 276: 239250 + 870 = 240120
Step 277: 240120 + 870 = 240990
Step 278: 240990 + 870 = 241860
Step 279: 241860 + 870 = 242730
Step 280: 242730 + 870 = 243600
Step 281: 243600 + 870 = 244470
Step 282: 244470 + 870 = 245340
Step 283: 245340 + 870 = 246210
Step 284: 246210 + 870 = 247080
Step 285: 247080 + 870 = 247950
Step 286: 247950 + 870 = 248820
Step 287: 248820 + 870 = 249690
Step 288: 249690 + 870 = 250560
Step 289: 250560 + 870 = 251430
Step 290: 251430 + 870 = 252300
Step 291: 252300 + 870 = 253170
Step 292: 253170 + 870 = 254040
Step 293: 254040 + 870 = 254910
Step 294: 254910 + 870 = 255780
Step 295: 255780 + 870 = 256650
Step 296: 256650 + 870 = 257520
Step 297: 257520 + 870 = 258390
Step 298: 258390 + 870 = 259260
Step 299: 259260 + 870 = 260130
Step 300: 260130 + 870 = 261000
Step 301: 261000 + 870 = 261870
Step 302: 261870 + 870 = 262740
Step 303: 262740 + 870 = 263610
Step 304: 263610 + 870 = 264480
Step 305: 264480 + 870 = 265350
Step 306: 265350 + 870 = 266220
Step 307: 266220 + 870 = 267090
Step 308: 267090 + 870 = 267960
Step 309: 267960 + 870 = 268830
Step 310: 268830 + 870 = 269700
Step 311: 269700 + 870 = 270570
Step 312: 270570 + 870 = 271440
Step 313: 271440 + 870 = 272310
Step 314: 272310 + 870 = 273180
Step 315: 273180 + 870 = 274050
Step 316: 274050 + 870 = 274920
Step 317: 274920 + 870 = 275790
Step 318: 275790 + 870 = 276660
Step 319: 276660 + 870 = 277530
Step 320: 277530 + 870 = 278400
Step 321: 278400 + 870 = 279270
Step 322: 279270 + 870 = 280140
Step 323: 280140 + 870 = 281010
Step 324: 281010 + 870 = 281880
Step 325: 281880 + 870 = 282750
Step 326: 282750 + 870 = 283620
Step 327: 283620 + 870 = 284490
Step 328: 284490 + 870 = 285360
Step 329: 285360 + 870 = 286230
Step 330: 286230 + 870 = 287100
Step 331: 287100 + 870 = 287970
Step 332: 287970 + 870 = 288840
Step 333: 288840 + 870 = 289710
Step 334: 289710 + 870 = 290580
Step 335: 290580 + 870 = 291450
Step 336: 291450 + 870 = 292320
Step 337: 292320 + 870 = 293190
Step 338: 293190 + 870 = 294060
Step 339: 294060 + 870 = 294930
Step 340: 294930 + 870 = 295800
Step 341: 295800 + 870 = 296670
Step 342: 296670 + 870 = 297540
Step 343: 297540 + 870 = 298410
Step 344: 298410 + 870 = 299280
Step 345: 299280 + 870 = 300150
Step 346: 300150 + 870 = 301020
Step 347: 301020 + 870 = 301890
Step 348: 301890 + 870 = 302760
Step 349: 302760 + 870 = 303630
Step 350: 303630 + 870 = 304500
Step 351: 304500 + 870 = 305370
Step 352: 305370 + 870 = 306240
Step 353: 306240 + 870 = 307110
Step 354: 307110 + 870 = 307980
Step 355: 307980 + 870 = 308850
Step 356: 308850 + 870 = 309720
Step 357: 309720 + 870 = 310590
Step 358: 310590 + 870 = 311460
Step 359: 311460 + 870 = 312330
Step 360: 312330 + 870 = 313200
Step 361: 313200 + 870 = 314070
Step 362: 314070 + 870 = 314940
Step 363: 314940 + 870 = 315810
Step 364: 315810 + 870 = 316680
Step 365: 316680 + 870 = 317550
Step 366: 317550 + 870 = 318420
Step 367: 318420 + 870 = 319290
Step 368: 319290 + 870 = 320160
Step 369: 320160 + 870 = 321030
Step 370: 321030 + 870 = 321900
Step 371: 321900 + 870 = 322770
Step 372: 322770 + 870 = 323640
Step 373: 323640 + 870 = 324510
Step 374: 324510 + 870 = 325380
Step 375: 325380 + 870 = 326250
Step 376: 326250 + 870 = 327120
Step 377: 327120 + 870 = 327990
Step 378: 327990 + 870 = 328860
Step 379: 328860 + 870 = 329730
Step 380: 329730 + 870 = 330600
Step 381: 330600 + 870 = 331470
Step 382: 331470 + 870 = 332340
Step 383: 332340 + 870 = 333210
Step 384: 333210 + 870 = 334080
Step 385: 334080 + 870 = 334950
Step 386: 334950 + 870 = 335820
Step 387: 335820 + 870 = 336690
Step 388: 336690 + 870 = 337560
Step 389: 337560 + 870 = 338430
Step 390: 338430 + 870 = 339300
Step 391: 339300 + 870 = 340170
Step 392: 340170 + 870 = 341040
Step 393: 341040 + 870 = 341910
Step 394: 341910 + 870 = 342780

So, 870*394 = 342780