Let's roll up our sleeves and solve this. We have 482 and we're going to multiply it by 21, essentially adding 482 to itself 21 times.
Step 1: 0 + 482 = 482
Step 2: 482 + 482 = 964
Step 3: 964 + 482 = 1446
Step 4: 1446 + 482 = 1928
Step 5: 1928 + 482 = 2410
Step 6: 2410 + 482 = 2892
Step 7: 2892 + 482 = 3374
Step 8: 3374 + 482 = 3856
Step 9: 3856 + 482 = 4338
Step 10: 4338 + 482 = 4820
Step 11: 4820 + 482 = 5302
Step 12: 5302 + 482 = 5784
Step 13: 5784 + 482 = 6266
Step 14: 6266 + 482 = 6748
Step 15: 6748 + 482 = 7230
Step 16: 7230 + 482 = 7712
Step 17: 7712 + 482 = 8194
Step 18: 8194 + 482 = 8676
Step 19: 8676 + 482 = 9158
Step 20: 9158 + 482 = 9640
Step 21: 9640 + 482 = 10122

So, 482*21 = 10122