The cake is a lie.
Fractions are hard--especially when it comes to giving up cake.
(Or is that CAKE form Wff-n-Proof?)
The half by what measure?
No! The cake is real! I saw it at the end!
the cake is equivalent to the continuum hypothesis.
Half of ten percent? Extra credit?
Outside of the great joke, parents now-a-days would yell at you. They do it to me and I teach college students.
To force Ben to learn what "half" of the cake means, just let Sarah choose which piece of cake she eats after Ben has cut the cake.
He should have said that the cake wasn't drawn to scale and marked her piece as being half.