Sure thing, let's get straight to it. We start with 203 and we're going to multiply it by 21, which means adding 203 to itself 21 times.
Step 1: 0 + 203 = 203
Step 2: 203 + 203 = 406
Step 3: 406 + 203 = 609
Step 4: 609 + 203 = 812
Step 5: 812 + 203 = 1015
Step 6: 1015 + 203 = 1218
Step 7: 1218 + 203 = 1421
Step 8: 1421 + 203 = 1624
Step 9: 1624 + 203 = 1827
Step 10: 1827 + 203 = 2030
Step 11: 2030 + 203 = 2233
Step 12: 2233 + 203 = 2436
Step 13: 2436 + 203 = 2639
Step 14: 2639 + 203 = 2842
Step 15: 2842 + 203 = 3045
Step 16: 3045 + 203 = 3248
Step 17: 3248 + 203 = 3451
Step 18: 3451 + 203 = 3654
Step 19: 3654 + 203 = 3857
Step 20: 3857 + 203 = 4060
Step 21: 4060 + 203 = 4263

So, 203*21 = 4263