Ideas: NCTM standards-based instruction-grades K-4 (ENC-007841) This National Council of Teachers of Mathematics (NCTM) book is meant for use as a resource for mathematics teachers in grades K to 4. The book consists of a collection of lessons from 1991 to 1994 issues of the journal ARITHMETIC TEACHER: MATHEMATICS EDUCATION THROUGH THE MIDDLE GRADES. Each activity sheet has been edited from its journal form for clarity and brevity.