This document provides examples and exercises for writing addition and subtraction expressions. It begins by having students write expressions for addition and subtraction of numbers and variables. Students are asked to draw bar diagrams to represent expressions and show that equivalent expressions can be written in different orders. The document emphasizes using parentheses correctly when subtracting a sum. Exercises practice writing expressions for various addition and subtraction scenarios and identifying when order matters. The goal is for students to be able to write expressions that accurately represent addition and subtraction operations.