Alright, let's solve this math problem step by step. First, we have the number 304. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 21. So, we're going to take the number 304 and add it to itself 21 times.
Step 1: 0 + 304 = 304
Step 2: 304 + 304 = 608
Step 3: 608 + 304 = 912
Step 4: 912 + 304 = 1216
Step 5: 1216 + 304 = 1520
Step 6: 1520 + 304 = 1824
Step 7: 1824 + 304 = 2128
Step 8: 2128 + 304 = 2432
Step 9: 2432 + 304 = 2736
Step 10: 2736 + 304 = 3040
Step 11: 3040 + 304 = 3344
Step 12: 3344 + 304 = 3648
Step 13: 3648 + 304 = 3952
Step 14: 3952 + 304 = 4256
Step 15: 4256 + 304 = 4560
Step 16: 4560 + 304 = 4864
Step 17: 4864 + 304 = 5168
Step 18: 5168 + 304 = 5472
Step 19: 5472 + 304 = 5776
Step 20: 5776 + 304 = 6080
Step 21: 6080 + 304 = 6384

So, 304*21 = 6384