Let's get this math done. We have 457 and we're going to multiply it by 3. This is the same as taking 457 and adding it to itself 3 times.
Step 1: 0 + 457 = 457
Step 2: 457 + 457 = 914
Step 3: 914 + 457 = 1371

So, 457*3 = 1371