OK, let's work through this together. We're starting with 3 and we're going to multiply it by 25, which means we add 3 to itself 25 times.
Step 1: 0 + 3 = 3
Step 2: 3 + 3 = 6
Step 3: 6 + 3 = 9
Step 4: 9 + 3 = 12
Step 5: 12 + 3 = 15
Step 6: 15 + 3 = 18
Step 7: 18 + 3 = 21
Step 8: 21 + 3 = 24
Step 9: 24 + 3 = 27
Step 10: 27 + 3 = 30
Step 11: 30 + 3 = 33
Step 12: 33 + 3 = 36
Step 13: 36 + 3 = 39
Step 14: 39 + 3 = 42
Step 15: 42 + 3 = 45
Step 16: 45 + 3 = 48
Step 17: 48 + 3 = 51
Step 18: 51 + 3 = 54
Step 19: 54 + 3 = 57
Step 20: 57 + 3 = 60
Step 21: 60 + 3 = 63
Step 22: 63 + 3 = 66
Step 23: 66 + 3 = 69
Step 24: 69 + 3 = 72
Step 25: 72 + 3 = 75

So, 3*25 = 75