Let's get this math done. We have 5 and we're going to multiply it by 18. This is the same as taking 5 and adding it to itself 18 times.
Step 1: 0 + 5 = 5
Step 2: 5 + 5 = 10
Step 3: 10 + 5 = 15
Step 4: 15 + 5 = 20
Step 5: 20 + 5 = 25
Step 6: 25 + 5 = 30
Step 7: 30 + 5 = 35
Step 8: 35 + 5 = 40
Step 9: 40 + 5 = 45
Step 10: 45 + 5 = 50
Step 11: 50 + 5 = 55
Step 12: 55 + 5 = 60
Step 13: 60 + 5 = 65
Step 14: 65 + 5 = 70
Step 15: 70 + 5 = 75
Step 16: 75 + 5 = 80
Step 17: 80 + 5 = 85
Step 18: 85 + 5 = 90

So, 5*18 = 90