<p>Pre-algebra should have been learned in junior high school (7th/8th grade).</p>
<p>Of course, that is a sad commentary on the state of K-12 in California if someone who actually graduated from high school needs to go back to pre-algebra. (However, since community colleges do exist in part to give people a second chance, there could still be some need for such courses even if K-12 were up to standard – but there would be less need.)</p>