Complex sentence: Connected Mathematics is a comprehensive, problem-centered curriculum designed for all students in grades 6-8 based on the NCTM standards that has been challenged for being ineffective in its treatment of basic mathematics skills.
Split into simpler sentences: Connected Mathematics is a comprehensive, problem-centered curriculum designed for all students in grades 6-8 based on the NCTM standards. Recently, this curriculum has been challenged for purported ineffectiveness in its treatment of basic mathematics skills.