This document contains examples of using variables in algebraic expressions and equations. It includes word problems involving variables representing unknown quantities like the number of hours worked, number of bus rides, cost of items, etc. Expressions are written to represent relationships between the variables and known values. Equations are set up and solved for the variable. Sample problems include calculating a tip amount, identifying properties of triangles, writing expressions for daily pay based on hours worked, and determining total costs based on item quantities and per unit prices.