According to the 1989 standards:

It is "essential that in grades 5-8, students explore algebraic concepts in an informal way."

In grades 9-12, the mathematics curriculum should include the informal exploration of calculus concept"

Principles and Standards for School Mathematics Information: Inside
[ Emphasis on finding "correct answers" reduced ]
[ High School Freshmen Calculus and Elementary Algebra ]
[ Traditional Content ] [ Technology ]
[ Math Appreciation & Culture ] [ Problem Solving ]
[ Mathematical Communications ] [ Math Wars ]
[ Innovative Curricula ] [ NCTM 2006 Recommendations ]
[ Humor & Culture ]