OK, let's work through this together. We're starting with 580 and we're going to multiply it by 85, which means we add 580 to itself 85 times.
Step 1: 0 + 580 = 580
Step 2: 580 + 580 = 1160
Step 3: 1160 + 580 = 1740
Step 4: 1740 + 580 = 2320
Step 5: 2320 + 580 = 2900
Step 6: 2900 + 580 = 3480
Step 7: 3480 + 580 = 4060
Step 8: 4060 + 580 = 4640
Step 9: 4640 + 580 = 5220
Step 10: 5220 + 580 = 5800
Step 11: 5800 + 580 = 6380
Step 12: 6380 + 580 = 6960
Step 13: 6960 + 580 = 7540
Step 14: 7540 + 580 = 8120
Step 15: 8120 + 580 = 8700
Step 16: 8700 + 580 = 9280
Step 17: 9280 + 580 = 9860
Step 18: 9860 + 580 = 10440
Step 19: 10440 + 580 = 11020
Step 20: 11020 + 580 = 11600
Step 21: 11600 + 580 = 12180
Step 22: 12180 + 580 = 12760
Step 23: 12760 + 580 = 13340
Step 24: 13340 + 580 = 13920
Step 25: 13920 + 580 = 14500
Step 26: 14500 + 580 = 15080
Step 27: 15080 + 580 = 15660
Step 28: 15660 + 580 = 16240
Step 29: 16240 + 580 = 16820
Step 30: 16820 + 580 = 17400
Step 31: 17400 + 580 = 17980
Step 32: 17980 + 580 = 18560
Step 33: 18560 + 580 = 19140
Step 34: 19140 + 580 = 19720
Step 35: 19720 + 580 = 20300
Step 36: 20300 + 580 = 20880
Step 37: 20880 + 580 = 21460
Step 38: 21460 + 580 = 22040
Step 39: 22040 + 580 = 22620
Step 40: 22620 + 580 = 23200
Step 41: 23200 + 580 = 23780
Step 42: 23780 + 580 = 24360
Step 43: 24360 + 580 = 24940
Step 44: 24940 + 580 = 25520
Step 45: 25520 + 580 = 26100
Step 46: 26100 + 580 = 26680
Step 47: 26680 + 580 = 27260
Step 48: 27260 + 580 = 27840
Step 49: 27840 + 580 = 28420
Step 50: 28420 + 580 = 29000
Step 51: 29000 + 580 = 29580
Step 52: 29580 + 580 = 30160
Step 53: 30160 + 580 = 30740
Step 54: 30740 + 580 = 31320
Step 55: 31320 + 580 = 31900
Step 56: 31900 + 580 = 32480
Step 57: 32480 + 580 = 33060
Step 58: 33060 + 580 = 33640
Step 59: 33640 + 580 = 34220
Step 60: 34220 + 580 = 34800
Step 61: 34800 + 580 = 35380
Step 62: 35380 + 580 = 35960
Step 63: 35960 + 580 = 36540
Step 64: 36540 + 580 = 37120
Step 65: 37120 + 580 = 37700
Step 66: 37700 + 580 = 38280
Step 67: 38280 + 580 = 38860
Step 68: 38860 + 580 = 39440
Step 69: 39440 + 580 = 40020
Step 70: 40020 + 580 = 40600
Step 71: 40600 + 580 = 41180
Step 72: 41180 + 580 = 41760
Step 73: 41760 + 580 = 42340
Step 74: 42340 + 580 = 42920
Step 75: 42920 + 580 = 43500
Step 76: 43500 + 580 = 44080
Step 77: 44080 + 580 = 44660
Step 78: 44660 + 580 = 45240
Step 79: 45240 + 580 = 45820
Step 80: 45820 + 580 = 46400
Step 81: 46400 + 580 = 46980
Step 82: 46980 + 580 = 47560
Step 83: 47560 + 580 = 48140
Step 84: 48140 + 580 = 48720
Step 85: 48720 + 580 = 49300

So, 580*85 = 49300