Sure thing, let's get straight to it. We start with 225 and we're going to multiply it by 4, which means adding 225 to itself 4 times.
Step 1: 0 + 225 = 225
Step 2: 225 + 225 = 450
Step 3: 450 + 225 = 675
Step 4: 675 + 225 = 900

So, 225*4 = 900