Without delay, let's solve this. We've got 662 and we will be multiplying it by 20, that is, adding 662 to itself 20 times.
Step 1: 0 + 662 = 662
Step 2: 662 + 662 = 1324
Step 3: 1324 + 662 = 1986
Step 4: 1986 + 662 = 2648
Step 5: 2648 + 662 = 3310
Step 6: 3310 + 662 = 3972
Step 7: 3972 + 662 = 4634
Step 8: 4634 + 662 = 5296
Step 9: 5296 + 662 = 5958
Step 10: 5958 + 662 = 6620
Step 11: 6620 + 662 = 7282
Step 12: 7282 + 662 = 7944
Step 13: 7944 + 662 = 8606
Step 14: 8606 + 662 = 9268
Step 15: 9268 + 662 = 9930
Step 16: 9930 + 662 = 10592
Step 17: 10592 + 662 = 11254
Step 18: 11254 + 662 = 11916
Step 19: 11916 + 662 = 12578
Step 20: 12578 + 662 = 13240

So, 662*20 = 13240