Let's roll up our sleeves and solve this. We have 981 and we're going to multiply it by 4, essentially adding 981 to itself 4 times.
Step 1: 0 + 981 = 981
Step 2: 981 + 981 = 1962
Step 3: 1962 + 981 = 2943
Step 4: 2943 + 981 = 3924

So, 981*4 = 3924