OK, let's crack this. We're given 991 and our task is to multiply it by 58. Essentially, we'll be adding 991 to itself 58 times.
Step 1: 0 + 991 = 991
Step 2: 991 + 991 = 1982
Step 3: 1982 + 991 = 2973
Step 4: 2973 + 991 = 3964
Step 5: 3964 + 991 = 4955
Step 6: 4955 + 991 = 5946
Step 7: 5946 + 991 = 6937
Step 8: 6937 + 991 = 7928
Step 9: 7928 + 991 = 8919
Step 10: 8919 + 991 = 9910
Step 11: 9910 + 991 = 10901
Step 12: 10901 + 991 = 11892
Step 13: 11892 + 991 = 12883
Step 14: 12883 + 991 = 13874
Step 15: 13874 + 991 = 14865
Step 16: 14865 + 991 = 15856
Step 17: 15856 + 991 = 16847
Step 18: 16847 + 991 = 17838
Step 19: 17838 + 991 = 18829
Step 20: 18829 + 991 = 19820
Step 21: 19820 + 991 = 20811
Step 22: 20811 + 991 = 21802
Step 23: 21802 + 991 = 22793
Step 24: 22793 + 991 = 23784
Step 25: 23784 + 991 = 24775
Step 26: 24775 + 991 = 25766
Step 27: 25766 + 991 = 26757
Step 28: 26757 + 991 = 27748
Step 29: 27748 + 991 = 28739
Step 30: 28739 + 991 = 29730
Step 31: 29730 + 991 = 30721
Step 32: 30721 + 991 = 31712
Step 33: 31712 + 991 = 32703
Step 34: 32703 + 991 = 33694
Step 35: 33694 + 991 = 34685
Step 36: 34685 + 991 = 35676
Step 37: 35676 + 991 = 36667
Step 38: 36667 + 991 = 37658
Step 39: 37658 + 991 = 38649
Step 40: 38649 + 991 = 39640
Step 41: 39640 + 991 = 40631
Step 42: 40631 + 991 = 41622
Step 43: 41622 + 991 = 42613
Step 44: 42613 + 991 = 43604
Step 45: 43604 + 991 = 44595
Step 46: 44595 + 991 = 45586
Step 47: 45586 + 991 = 46577
Step 48: 46577 + 991 = 47568
Step 49: 47568 + 991 = 48559
Step 50: 48559 + 991 = 49550
Step 51: 49550 + 991 = 50541
Step 52: 50541 + 991 = 51532
Step 53: 51532 + 991 = 52523
Step 54: 52523 + 991 = 53514
Step 55: 53514 + 991 = 54505
Step 56: 54505 + 991 = 55496
Step 57: 55496 + 991 = 56487
Step 58: 56487 + 991 = 57478

So, 991*58 = 57478