Let's get this math done. We have 903 and we're going to multiply it by 4. This is the same as taking 903 and adding it to itself 4 times.
Step 1: 0 + 903 = 903
Step 2: 903 + 903 = 1806
Step 3: 1806 + 903 = 2709
Step 4: 2709 + 903 = 3612

So, 903*4 = 3612