You have \(4\frac{1}{2}\) apples left.
You have 5 whole apples, you took one whole apple out, which equals 4 whole apples left. Then with the whole apple you took out, you ate \(\frac{1}{2}\) of it.
Jack ate \(\frac{1}{2}\) of an apple in 5 apples.
If you say that Jack ate \(\frac{1}{2}\) of 3 apples, then he ate \(1\frac{1}{2}\) apples. So there isn't any difference when he ate \(\frac{1}{2}\) of an apple.
