Without delay, let's solve this. We've got 390 and we will be multiplying it by 4, that is, adding 390 to itself 4 times.
Step 1: 0 + 390 = 390
Step 2: 390 + 390 = 780
Step 3: 780 + 390 = 1170
Step 4: 1170 + 390 = 1560

So, 390*4 = 1560