Let's get this math done. We have 456 and we're going to multiply it by 3. This is the same as taking 456 and adding it to itself 3 times.
Step 1: 0 + 456 = 456
Step 2: 456 + 456 = 912
Step 3: 912 + 456 = 1368

So, 456*3 = 1368