Without delay, let's solve this. We've got 541 and we will be multiplying it by 15, that is, adding 541 to itself 15 times.
Step 1: 0 + 541 = 541
Step 2: 541 + 541 = 1082
Step 3: 1082 + 541 = 1623
Step 4: 1623 + 541 = 2164
Step 5: 2164 + 541 = 2705
Step 6: 2705 + 541 = 3246
Step 7: 3246 + 541 = 3787
Step 8: 3787 + 541 = 4328
Step 9: 4328 + 541 = 4869
Step 10: 4869 + 541 = 5410
Step 11: 5410 + 541 = 5951
Step 12: 5951 + 541 = 6492
Step 13: 6492 + 541 = 7033
Step 14: 7033 + 541 = 7574
Step 15: 7574 + 541 = 8115

So, 541*15 = 8115