OK, let's work through this together. We're starting with 793 and we're going to multiply it by 4, which means we add 793 to itself 4 times.
Step 1: 0 + 793 = 793
Step 2: 793 + 793 = 1586
Step 3: 1586 + 793 = 2379
Step 4: 2379 + 793 = 3172

So, 793*4 = 3172