Without delay, let's solve this. We've got 61 and we will be multiplying it by 21, that is, adding 61 to itself 21 times.
Step 1: 0 + 61 = 61
Step 2: 61 + 61 = 122
Step 3: 122 + 61 = 183
Step 4: 183 + 61 = 244
Step 5: 244 + 61 = 305
Step 6: 305 + 61 = 366
Step 7: 366 + 61 = 427
Step 8: 427 + 61 = 488
Step 9: 488 + 61 = 549
Step 10: 549 + 61 = 610
Step 11: 610 + 61 = 671
Step 12: 671 + 61 = 732
Step 13: 732 + 61 = 793
Step 14: 793 + 61 = 854
Step 15: 854 + 61 = 915
Step 16: 915 + 61 = 976
Step 17: 976 + 61 = 1037
Step 18: 1037 + 61 = 1098
Step 19: 1098 + 61 = 1159
Step 20: 1159 + 61 = 1220
Step 21: 1220 + 61 = 1281

So, 61*21 = 1281