Alright, let's solve this math problem step by step. First, we have the number 600. 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 600 and add it to itself 15 times.
Step 1: 0 + 600 = 600
Step 2: 600 + 600 = 1200
Step 3: 1200 + 600 = 1800
Step 4: 1800 + 600 = 2400
Step 5: 2400 + 600 = 3000
Step 6: 3000 + 600 = 3600
Step 7: 3600 + 600 = 4200
Step 8: 4200 + 600 = 4800
Step 9: 4800 + 600 = 5400
Step 10: 5400 + 600 = 6000
Step 11: 6000 + 600 = 6600
Step 12: 6600 + 600 = 7200
Step 13: 7200 + 600 = 7800
Step 14: 7800 + 600 = 8400
Step 15: 8400 + 600 = 9000

So, 600*15 = 9000