Variables
- 2. Consider the population of Florida, the area of Colorado, and the flight time from Philadelphia to San Francisco. Which of these has a value that varies?
- 3. A mathematical quantity can be measured or counted. Some quantities are constant (like the area of Colorado) and some vary (like the population of Florida). The quantities that vary are called variables. In Algebra symbols are used to represent variables (or unknown quantities) and numbers are used to represent constants (or quantities that we know). An algebraic expression is a math phrase that uses at least one variable and a numerical expression is a math phrase that uses only numbers.
- 4. In Algebra, words with in a phrase are translated into numbers, letters, and operation symbols. Words such as “more than”, “times”, “less than”, and “each/every” translate into operations: “+”, “x”, “-”, and “÷”. For example: “32 more than a number” would translate into “32 + n”. “8 times a number” becomes “8 x n or 8n (often the multiplication symbol is not written…it’s too easily confused with a variable) “9 less than a number” becomes “n − 9” (less than phrases are flipped) “9 less than the quotient of 6 and a number” becomes “6/n − 9” (quotient means divide)
- 5. Now try the Lesson Check for this section.