Without delay, let's solve this. We've got 172 and we will be multiplying it by 4, that is, adding 172 to itself 4 times.
Step 1: 0 + 172 = 172
Step 2: 172 + 172 = 344
Step 3: 344 + 172 = 516
Step 4: 516 + 172 = 688

So, 172*4 = 688