Alright, let's solve this math problem step by step. First, we have the number 625. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 15. So, we're going to take the number 625 and add it to itself 15 times.
Step 1: 0 + 625 = 625
Step 2: 625 + 625 = 1250
Step 3: 1250 + 625 = 1875
Step 4: 1875 + 625 = 2500
Step 5: 2500 + 625 = 3125
Step 6: 3125 + 625 = 3750
Step 7: 3750 + 625 = 4375
Step 8: 4375 + 625 = 5000
Step 9: 5000 + 625 = 5625
Step 10: 5625 + 625 = 6250
Step 11: 6250 + 625 = 6875
Step 12: 6875 + 625 = 7500
Step 13: 7500 + 625 = 8125
Step 14: 8125 + 625 = 8750
Step 15: 8750 + 625 = 9375

So, 625*15 = 9375