The document discusses writing variable expressions to represent word phrases and vice versa. It provides examples of commonly used variables like x and y and explains that variables are placeholders that represent unknown quantities. The document shows how to translate phrases like "four more than a number" to the expression x+4. It also gives the reverse translation from expressions like 3(x+10) to word phrases. Examples are provided to demonstrate translating real world word problems into variable expressions and vice versa. Homework problems from the textbook are assigned.