Actually, they haven't. For the most part, they've never read anything critically (or even really read anything period), and the crank-turning and hoo-ha that goes in math class certainly isn't mathematics.

So by the time they hit Calculus and Shakespeare, they're in year 11 of their time in a velvet jail and have learned to very adequately mimic the bizarre squawking the guards insist is requisite for passage to The Island.

What they have not done is mathematics or reading in any real sense.