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Lesson plan

Solve multiplicative comparison word problems with missing factors by using equations with a symbol for the unknown

teaches Common Core State Standards MP4 http://corestandards.org/Math/Practice/MP4
teaches Common Core State Standards MP2 http://corestandards.org/Math/Practice/MP2
teaches Common Core State Standards 4.OA.A.2 http://corestandards.org/Math/Content/4/OA/A/2
teaches Common Core State Standards 4.NBT.A.3 http://corestandards.org/Math/Content/4/NBT/A/3

Solve multiplicative comparison word problems with missing factors by using equations with a symbol for the unknown

Big Ideas: In a multiplicative comparison, if the group size or the number of groups is unknown, this is a missing factor, which can be solved with division. Multiplying by x is the inverse of dividing by x. This lesson builds on students' understanding of multiplicative comparison and the inverse relationship between multiplication and division. The task asks students to determine quantities of items given in terms of multiplicative comparisons in which factors are unknown. Vocabulary: multiplicative comparison, factor, product, division, inverse, quotient, group size, multiplier Special Materials: graph paper linking cubes base ten blocks