OK, let's crack this. We're given 220 and our task is to multiply it by 21. Essentially, we'll be adding 220 to itself 21 times.
Step 1: 0 + 220 = 220
Step 2: 220 + 220 = 440
Step 3: 440 + 220 = 660
Step 4: 660 + 220 = 880
Step 5: 880 + 220 = 1100
Step 6: 1100 + 220 = 1320
Step 7: 1320 + 220 = 1540
Step 8: 1540 + 220 = 1760
Step 9: 1760 + 220 = 1980
Step 10: 1980 + 220 = 2200
Step 11: 2200 + 220 = 2420
Step 12: 2420 + 220 = 2640
Step 13: 2640 + 220 = 2860
Step 14: 2860 + 220 = 3080
Step 15: 3080 + 220 = 3300
Step 16: 3300 + 220 = 3520
Step 17: 3520 + 220 = 3740
Step 18: 3740 + 220 = 3960
Step 19: 3960 + 220 = 4180
Step 20: 4180 + 220 = 4400
Step 21: 4400 + 220 = 4620

So, 220*21 = 4620