CKMath Unit 4: Relating Multiplication to Division
Focus:
This unit introduces students to the concept of division and its relationship to multiplication. Previously, students learned that multiplication can be understood in terms of equal-size groups. The expression 5 x 2 can represent the total number of objects when there are 5 groups of 2 objects, or when there are 2 groups of 5 objects. Here, students make sense of division also in terms of equal-size groups. For instance, the expression 30 ÷ 5 can represent putting 30 objects into 5 equal groups, or putting 30 objects into groups of 5. They see that, in general, dividing can mean finding the size of each group, or finding the number of equal groups. Students use the relationship between multiplication and division to develop fluency with single-digit multiplication and division facts. They continue to reason about products of two numbers in terms of the area of rectangles whose side lengths represent the factors, decomposing side lengths and applying properties of operations along the way. As they multiply numbers greater than 10, students see that it is helpful to decompose the two-digit factor into tens and ones and distribute the multiplication. Toward the end of the unit, students solve two-step problems that involve all four operations.
Number of Lessons: 21 and 1 optional
Instruction Time:
Approximately 60 minutes
(Please note that each lesson is designed for one instructional block, and may be divided into shorter or longer segments based on teacher pacing and student needs.)
