"Students must learn mathematics with understanding, actively building new knowledge from experience and prior knowledge." From the Principles for School Mathematics of NCTM standards, copyright NCTM 2000-2004.

Yet sometimes when students are learning mathematics, they learn misconceptions and adopt erroneous procedures despite the best efforts of their teacher. This book was written to help teachers to detect the systematic errors many students make-whether using paper and pencil, or calculators or computers. Emphasizing concepts and skills, in accordance with the NCTM...