Alright, let's solve this math problem step by step. First, we have the number 963. 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 963 and add it to itself 21 times.
Step 1: 0 + 963 = 963
Step 2: 963 + 963 = 1926
Step 3: 1926 + 963 = 2889
Step 4: 2889 + 963 = 3852
Step 5: 3852 + 963 = 4815
Step 6: 4815 + 963 = 5778
Step 7: 5778 + 963 = 6741
Step 8: 6741 + 963 = 7704
Step 9: 7704 + 963 = 8667
Step 10: 8667 + 963 = 9630
Step 11: 9630 + 963 = 10593
Step 12: 10593 + 963 = 11556
Step 13: 11556 + 963 = 12519
Step 14: 12519 + 963 = 13482
Step 15: 13482 + 963 = 14445
Step 16: 14445 + 963 = 15408
Step 17: 15408 + 963 = 16371
Step 18: 16371 + 963 = 17334
Step 19: 17334 + 963 = 18297
Step 20: 18297 + 963 = 19260
Step 21: 19260 + 963 = 20223

So, 963*21 = 20223