Lesson 1.1 Using Variables

1.1 – Using Variables Goals / “I can…” Model relationships with variables Model relationships with equations

1.1 – Using Variables What is a variable? A variable is a symbol, usually a letter, that represents one or more numbers. x, y, z, a, b, c

1.1 – Using Variables What is an expression? An algebraic expression is a mathematical phrase that can have numbers, variables and operation symbols.

1.1 – Using Variables Example 1 – words used in algebra More than, sum, put together + Less, Difference of, - Product x or * Quotient ÷ or /

1.1 – Using Variables Example 2 – writing an algebraic expression The sum of n and 8 Six less than b 5 more than a number tripled

1.1 – Using Variables An equation is a mathematical sentence that uses an equal sign.

1.1 – Using Variables So what’s the difference between an algebraic expression and an equation?

1.1 – Using Variables An open sentence is an equation that contains one or more variables.

1.1 – Using Variables Example 3 – Writing an equation Write an equation to show the total income from selling tickets to a school play for $5 each.

1.1 – Using Variables Example 4 – Writing an equation from data Gallons Used Miles Traveled