Alright, let's solve this math problem step by step. First, we have the number 594. 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 594 and add it to itself 21 times.
Step 1: 0 + 594 = 594
Step 2: 594 + 594 = 1188
Step 3: 1188 + 594 = 1782
Step 4: 1782 + 594 = 2376
Step 5: 2376 + 594 = 2970
Step 6: 2970 + 594 = 3564
Step 7: 3564 + 594 = 4158
Step 8: 4158 + 594 = 4752
Step 9: 4752 + 594 = 5346
Step 10: 5346 + 594 = 5940
Step 11: 5940 + 594 = 6534
Step 12: 6534 + 594 = 7128
Step 13: 7128 + 594 = 7722
Step 14: 7722 + 594 = 8316
Step 15: 8316 + 594 = 8910
Step 16: 8910 + 594 = 9504
Step 17: 9504 + 594 = 10098
Step 18: 10098 + 594 = 10692
Step 19: 10692 + 594 = 11286
Step 20: 11286 + 594 = 11880
Step 21: 11880 + 594 = 12474

So, 594*21 = 12474