# Formative Assessment Lessons

A *Formative Assessment Lesson* (also known as a Classroom Challenge) is a carefully designed lesson intended to both support teachers in examining how students understand the mathematics of the unit and simultaneously give students opportunities to revisit and deepen their understanding of mathematics.

These lessons were created by the Mathematics Assessment Project and were carefully tested in classrooms around the world. As such, we recommend teachers make modifications to either the structure of the lessons or the materials used during the lessons * only* after careful consideration of how these changes support their mathematical goals with their students, and any changes should be carefully tested. This guide provides more information on how to use these Formative Assessment Lessons.