The "Key To Measurement" Books 1-4 Complete Set is a series of textbooks focused on the subject area of Mathematics, specifically on measurement. Authored by Betsy Franco and published by Key Curriculum Press, these workbooks provide comprehensive coverage and practice exercises for students. With a booklet/paperback format, these books offer a thorough curriculum for homeschooling or educational purposes, ensuring a solid understanding of measurement concepts. Additionally, the set includes answers and notes for instructors or parents looking to guide students through the material effectively.