Let's roll up our sleeves and solve this. We have 787 and we're going to multiply it by 4, essentially adding 787 to itself 4 times.
Step 1: 0 + 787 = 787
Step 2: 787 + 787 = 1574
Step 3: 1574 + 787 = 2361
Step 4: 2361 + 787 = 3148

So, 787*4 = 3148