OK, let's crack this. We're given 685 and our task is to multiply it by 4. Essentially, we'll be adding 685 to itself 4 times.
Step 1: 0 + 685 = 685
Step 2: 685 + 685 = 1370
Step 3: 1370 + 685 = 2055
Step 4: 2055 + 685 = 2740

So, 685*4 = 2740