See a gap in understanding? Mine it to move your students forward. How good are you at exploiting students’ mathematical mistakes? In this remarkable book, the authors remind us that student mistakes are not random, and when we take the time to “mine the gap,” we can dispel misunderstandings before they take root. Included are 180 downloadable high—quality tasks, aligned to the standards and big ideas of grades 6–8 mathematics. Each task includes sample student work, commentary on strengths and gaps, and next instructional steps. Whether you use this bank of tasks for instruction or assessment, you will love how it helps you easily identify students’ thinking and then follow up with instruction that brings clear, complete understanding.