OK, let's work through this together. We're starting with 68 and we're going to multiply it by 4, which means we add 68 to itself 4 times.
Step 1: 0 + 68 = 68
Step 2: 68 + 68 = 136
Step 3: 136 + 68 = 204
Step 4: 204 + 68 = 272

So, 68*4 = 272