Multiplicative thinking is a set of essential understandings about the patterns within and between numbers. From skip counting to multiples, from "groups of" and "rows of" to the multiplication of larger numbers using the distributive property, from T-tables to algebraic reasoning, multiplicative thinking is has a huge role to play in developing a solid sense of number. This 220 page volume contains 40 multi-aged lessons designed to promote deep understanding of multiplicative ideas. Rich open-ended tasks framed around the big math ideas, literature connections and real-world problems, written practice and engaging purposeful games, as well as assessment tasks are featured in this resource for grades 3 to 8 teachers.