OK, let's crack this. We're given 880 and our task is to multiply it by 89. Essentially, we'll be adding 880 to itself 89 times.
Step 1: 0 + 880 = 880
Step 2: 880 + 880 = 1760
Step 3: 1760 + 880 = 2640
Step 4: 2640 + 880 = 3520
Step 5: 3520 + 880 = 4400
Step 6: 4400 + 880 = 5280
Step 7: 5280 + 880 = 6160
Step 8: 6160 + 880 = 7040
Step 9: 7040 + 880 = 7920
Step 10: 7920 + 880 = 8800
Step 11: 8800 + 880 = 9680
Step 12: 9680 + 880 = 10560
Step 13: 10560 + 880 = 11440
Step 14: 11440 + 880 = 12320
Step 15: 12320 + 880 = 13200
Step 16: 13200 + 880 = 14080
Step 17: 14080 + 880 = 14960
Step 18: 14960 + 880 = 15840
Step 19: 15840 + 880 = 16720
Step 20: 16720 + 880 = 17600
Step 21: 17600 + 880 = 18480
Step 22: 18480 + 880 = 19360
Step 23: 19360 + 880 = 20240
Step 24: 20240 + 880 = 21120
Step 25: 21120 + 880 = 22000
Step 26: 22000 + 880 = 22880
Step 27: 22880 + 880 = 23760
Step 28: 23760 + 880 = 24640
Step 29: 24640 + 880 = 25520
Step 30: 25520 + 880 = 26400
Step 31: 26400 + 880 = 27280
Step 32: 27280 + 880 = 28160
Step 33: 28160 + 880 = 29040
Step 34: 29040 + 880 = 29920
Step 35: 29920 + 880 = 30800
Step 36: 30800 + 880 = 31680
Step 37: 31680 + 880 = 32560
Step 38: 32560 + 880 = 33440
Step 39: 33440 + 880 = 34320
Step 40: 34320 + 880 = 35200
Step 41: 35200 + 880 = 36080
Step 42: 36080 + 880 = 36960
Step 43: 36960 + 880 = 37840
Step 44: 37840 + 880 = 38720
Step 45: 38720 + 880 = 39600
Step 46: 39600 + 880 = 40480
Step 47: 40480 + 880 = 41360
Step 48: 41360 + 880 = 42240
Step 49: 42240 + 880 = 43120
Step 50: 43120 + 880 = 44000
Step 51: 44000 + 880 = 44880
Step 52: 44880 + 880 = 45760
Step 53: 45760 + 880 = 46640
Step 54: 46640 + 880 = 47520
Step 55: 47520 + 880 = 48400
Step 56: 48400 + 880 = 49280
Step 57: 49280 + 880 = 50160
Step 58: 50160 + 880 = 51040
Step 59: 51040 + 880 = 51920
Step 60: 51920 + 880 = 52800
Step 61: 52800 + 880 = 53680
Step 62: 53680 + 880 = 54560
Step 63: 54560 + 880 = 55440
Step 64: 55440 + 880 = 56320
Step 65: 56320 + 880 = 57200
Step 66: 57200 + 880 = 58080
Step 67: 58080 + 880 = 58960
Step 68: 58960 + 880 = 59840
Step 69: 59840 + 880 = 60720
Step 70: 60720 + 880 = 61600
Step 71: 61600 + 880 = 62480
Step 72: 62480 + 880 = 63360
Step 73: 63360 + 880 = 64240
Step 74: 64240 + 880 = 65120
Step 75: 65120 + 880 = 66000
Step 76: 66000 + 880 = 66880
Step 77: 66880 + 880 = 67760
Step 78: 67760 + 880 = 68640
Step 79: 68640 + 880 = 69520
Step 80: 69520 + 880 = 70400
Step 81: 70400 + 880 = 71280
Step 82: 71280 + 880 = 72160
Step 83: 72160 + 880 = 73040
Step 84: 73040 + 880 = 73920
Step 85: 73920 + 880 = 74800
Step 86: 74800 + 880 = 75680
Step 87: 75680 + 880 = 76560
Step 88: 76560 + 880 = 77440
Step 89: 77440 + 880 = 78320

So, 880*89 = 78320