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 170. So, we're going to take the number 870 and add it to itself 170 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

So, 870*170 = 147900