Alright, let's solve this math problem step by step. First, we have the number 405. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 24. So, we're going to take the number 405 and add it to itself 24 times.
Step 1: 0 + 405 = 405
Step 2: 405 + 405 = 810
Step 3: 810 + 405 = 1215
Step 4: 1215 + 405 = 1620
Step 5: 1620 + 405 = 2025
Step 6: 2025 + 405 = 2430
Step 7: 2430 + 405 = 2835
Step 8: 2835 + 405 = 3240
Step 9: 3240 + 405 = 3645
Step 10: 3645 + 405 = 4050
Step 11: 4050 + 405 = 4455
Step 12: 4455 + 405 = 4860
Step 13: 4860 + 405 = 5265
Step 14: 5265 + 405 = 5670
Step 15: 5670 + 405 = 6075
Step 16: 6075 + 405 = 6480
Step 17: 6480 + 405 = 6885
Step 18: 6885 + 405 = 7290
Step 19: 7290 + 405 = 7695
Step 20: 7695 + 405 = 8100
Step 21: 8100 + 405 = 8505
Step 22: 8505 + 405 = 8910
Step 23: 8910 + 405 = 9315
Step 24: 9315 + 405 = 9720

So, 405*24 = 9720