Let's roll up our sleeves and solve this. We have 687 and we're going to multiply it by 4, essentially adding 687 to itself 4 times.
Step 1: 0 + 687 = 687
Step 2: 687 + 687 = 1374
Step 3: 1374 + 687 = 2061
Step 4: 2061 + 687 = 2748

So, 687*4 = 2748