OK, let's work through this together. We're starting with 998 and we're going to multiply it by 4, which means we add 998 to itself 4 times.
Step 1: 0 + 998 = 998
Step 2: 998 + 998 = 1996
Step 3: 1996 + 998 = 2994
Step 4: 2994 + 998 = 3992

So, 998*4 = 3992