Reform mathematics is an approach to mathematics education, particularly in North America. It is based on principles explained in 1989 by the National Council of Teachers of Mathematics (NCTM). The NCTM document, Curriculum and Evaluation Standards for School Mathematics, attempted to set forth a vision for K-12 (ages 5-18) mathematics education in the United States and Canada. Their recommendations were adopted by many education agencies, from local to federal levels through the 1990s.