Equivalent Fractions

You order one pizza and eat half of it. Your friend orders the same pizza, cuts it into four slices, and eats two of them. You both ate the same amount — yet you'd swear you ate ½ and she ate 2/4. Two different fractions, one identical stomach. How can different numbers describe the exact same quantity? There's a hidden lever inside every fraction, and pulling it changes the look without changing the value.