Without delay, let's solve this. We've got 159 and we will be multiplying it by 4, that is, adding 159 to itself 4 times.
Step 1: 0 + 159 = 159
Step 2: 159 + 159 = 318
Step 3: 318 + 159 = 477
Step 4: 477 + 159 = 636

So, 159*4 = 636