Let's get this math done. We have 879 and we're going to multiply it by 4. This is the same as taking 879 and adding it to itself 4 times.
Step 1: 0 + 879 = 879
Step 2: 879 + 879 = 1758
Step 3: 1758 + 879 = 2637
Step 4: 2637 + 879 = 3516

So, 879*4 = 3516