This set of two Tarsia jigsaw math puzzles covers both greatest common factor (also know as highest common factor or HCF) and least common multiple (also known as lowest common multiple or LCM) of pairs of numbers. Each puzzle requires your students to solve the 30 questions to fit the 24 triangular pieces together into one large hexagon. Great as a starter settling activity for math lessons in 6th grade and beyond or as a group task for students to discuss their understanding with each other, p