## Unit 2

Unit 2 is typically a six-week unit taught in November and December.

### Unit Overview

Mathematics is a language consisting of carefully defined terms and symbols. In this unit, students develop an understanding of mathematical language as they continue to extend their knowledge of numeric patterns and relationships.
Mastery of basic multiplication facts helps students make reasonable estimates and perform operations with large numbers. Knowledge of the relationship between the inverse operations of multiplication and division is important for developing fluency with division facts. In Grade 3, students mastered multiplication facts for 0, 1, 2, 5, and 10 using a variety of models including arrays and skip counting. They examined the numerical patterns found in multiplication using materials such as a Hundreds Chart. In this unit, fact families for 3, 4, 6, 7, 8, and 9 are explored and students practice strategies to attain mastery. Factor and multiple concepts are developed to provide the foundation students need for understanding common multiples and common factors in Grade 5. Practice with parentheses used as grouping symbols enables students to symbolically group numbers to compute efficiently. Prior to Grade 4, students learned that the relationships among known quantities can be expressed using numbers and symbols (7 + 5 < 13). In this unit, students learn that unknown quantities may be represented with letters. They explore the concept of variable as a specific quantity and as a varying quantity.