OK, let's crack this. We're given 660 and our task is to multiply it by 155. Essentially, we'll be adding 660 to itself 155 times.
Step 1: 0 + 660 = 660
Step 2: 660 + 660 = 1320
Step 3: 1320 + 660 = 1980
Step 4: 1980 + 660 = 2640
Step 5: 2640 + 660 = 3300
Step 6: 3300 + 660 = 3960
Step 7: 3960 + 660 = 4620
Step 8: 4620 + 660 = 5280
Step 9: 5280 + 660 = 5940
Step 10: 5940 + 660 = 6600
Step 11: 6600 + 660 = 7260
Step 12: 7260 + 660 = 7920
Step 13: 7920 + 660 = 8580
Step 14: 8580 + 660 = 9240
Step 15: 9240 + 660 = 9900
Step 16: 9900 + 660 = 10560
Step 17: 10560 + 660 = 11220
Step 18: 11220 + 660 = 11880
Step 19: 11880 + 660 = 12540
Step 20: 12540 + 660 = 13200
Step 21: 13200 + 660 = 13860
Step 22: 13860 + 660 = 14520
Step 23: 14520 + 660 = 15180
Step 24: 15180 + 660 = 15840
Step 25: 15840 + 660 = 16500
Step 26: 16500 + 660 = 17160
Step 27: 17160 + 660 = 17820
Step 28: 17820 + 660 = 18480
Step 29: 18480 + 660 = 19140
Step 30: 19140 + 660 = 19800
Step 31: 19800 + 660 = 20460
Step 32: 20460 + 660 = 21120
Step 33: 21120 + 660 = 21780
Step 34: 21780 + 660 = 22440
Step 35: 22440 + 660 = 23100
Step 36: 23100 + 660 = 23760
Step 37: 23760 + 660 = 24420
Step 38: 24420 + 660 = 25080
Step 39: 25080 + 660 = 25740
Step 40: 25740 + 660 = 26400
Step 41: 26400 + 660 = 27060
Step 42: 27060 + 660 = 27720
Step 43: 27720 + 660 = 28380
Step 44: 28380 + 660 = 29040
Step 45: 29040 + 660 = 29700
Step 46: 29700 + 660 = 30360
Step 47: 30360 + 660 = 31020
Step 48: 31020 + 660 = 31680
Step 49: 31680 + 660 = 32340
Step 50: 32340 + 660 = 33000
Step 51: 33000 + 660 = 33660
Step 52: 33660 + 660 = 34320
Step 53: 34320 + 660 = 34980
Step 54: 34980 + 660 = 35640
Step 55: 35640 + 660 = 36300
Step 56: 36300 + 660 = 36960
Step 57: 36960 + 660 = 37620
Step 58: 37620 + 660 = 38280
Step 59: 38280 + 660 = 38940
Step 60: 38940 + 660 = 39600
Step 61: 39600 + 660 = 40260
Step 62: 40260 + 660 = 40920
Step 63: 40920 + 660 = 41580
Step 64: 41580 + 660 = 42240
Step 65: 42240 + 660 = 42900
Step 66: 42900 + 660 = 43560
Step 67: 43560 + 660 = 44220
Step 68: 44220 + 660 = 44880
Step 69: 44880 + 660 = 45540
Step 70: 45540 + 660 = 46200
Step 71: 46200 + 660 = 46860
Step 72: 46860 + 660 = 47520
Step 73: 47520 + 660 = 48180
Step 74: 48180 + 660 = 48840
Step 75: 48840 + 660 = 49500
Step 76: 49500 + 660 = 50160
Step 77: 50160 + 660 = 50820
Step 78: 50820 + 660 = 51480
Step 79: 51480 + 660 = 52140
Step 80: 52140 + 660 = 52800
Step 81: 52800 + 660 = 53460
Step 82: 53460 + 660 = 54120
Step 83: 54120 + 660 = 54780
Step 84: 54780 + 660 = 55440
Step 85: 55440 + 660 = 56100
Step 86: 56100 + 660 = 56760
Step 87: 56760 + 660 = 57420
Step 88: 57420 + 660 = 58080
Step 89: 58080 + 660 = 58740
Step 90: 58740 + 660 = 59400
Step 91: 59400 + 660 = 60060
Step 92: 60060 + 660 = 60720
Step 93: 60720 + 660 = 61380
Step 94: 61380 + 660 = 62040
Step 95: 62040 + 660 = 62700
Step 96: 62700 + 660 = 63360
Step 97: 63360 + 660 = 64020
Step 98: 64020 + 660 = 64680
Step 99: 64680 + 660 = 65340
Step 100: 65340 + 660 = 66000
Step 101: 66000 + 660 = 66660
Step 102: 66660 + 660 = 67320
Step 103: 67320 + 660 = 67980
Step 104: 67980 + 660 = 68640
Step 105: 68640 + 660 = 69300
Step 106: 69300 + 660 = 69960
Step 107: 69960 + 660 = 70620
Step 108: 70620 + 660 = 71280
Step 109: 71280 + 660 = 71940
Step 110: 71940 + 660 = 72600
Step 111: 72600 + 660 = 73260
Step 112: 73260 + 660 = 73920
Step 113: 73920 + 660 = 74580
Step 114: 74580 + 660 = 75240
Step 115: 75240 + 660 = 75900
Step 116: 75900 + 660 = 76560
Step 117: 76560 + 660 = 77220
Step 118: 77220 + 660 = 77880
Step 119: 77880 + 660 = 78540
Step 120: 78540 + 660 = 79200
Step 121: 79200 + 660 = 79860
Step 122: 79860 + 660 = 80520
Step 123: 80520 + 660 = 81180
Step 124: 81180 + 660 = 81840
Step 125: 81840 + 660 = 82500
Step 126: 82500 + 660 = 83160
Step 127: 83160 + 660 = 83820
Step 128: 83820 + 660 = 84480
Step 129: 84480 + 660 = 85140
Step 130: 85140 + 660 = 85800
Step 131: 85800 + 660 = 86460
Step 132: 86460 + 660 = 87120
Step 133: 87120 + 660 = 87780
Step 134: 87780 + 660 = 88440
Step 135: 88440 + 660 = 89100
Step 136: 89100 + 660 = 89760
Step 137: 89760 + 660 = 90420
Step 138: 90420 + 660 = 91080
Step 139: 91080 + 660 = 91740
Step 140: 91740 + 660 = 92400
Step 141: 92400 + 660 = 93060
Step 142: 93060 + 660 = 93720
Step 143: 93720 + 660 = 94380
Step 144: 94380 + 660 = 95040
Step 145: 95040 + 660 = 95700
Step 146: 95700 + 660 = 96360
Step 147: 96360 + 660 = 97020
Step 148: 97020 + 660 = 97680
Step 149: 97680 + 660 = 98340
Step 150: 98340 + 660 = 99000
Step 151: 99000 + 660 = 99660
Step 152: 99660 + 660 = 100320
Step 153: 100320 + 660 = 100980
Step 154: 100980 + 660 = 101640
Step 155: 101640 + 660 = 102300

So, 660*155 = 102300