Math Words to Know LESSON GOAL: I can recognize key math terms and be able to use them in real world situations.

expression – mathematical phrase that contains numbers, variables, and operators but no equal sign 2x – 4 3+ x 2 + 2

equation – written statement showing the equality of two expressions 2x – 4 = y 3+ x = = 5 - 1

function – a relationship or expression involving one or more variables that compares input and output y = 2x shows the relationship between x and y with x representing the input (plugging in numbers) and y representing the output (answer).

coefficient – number …-2, -1, 0, 1, 2, ….

variable – letter that represents a number x, y, z, a, b, … the letter does not matter as long as you know what it represents

simplify – to make an expression simpler; solve when possible 2x + 3 – 5 2x - 2 2x + 3 – 5x -3x + 3 (x + 1) (2 – 2x) 2x – 2x + 2 – 2x -2x

substitute – putting numbers in for variables 2x + 3 when x = 2 2(2)

plug in– substitute a number for a letter 2x + 3 when x = 2 2(2)

solve for y – plug a number in for x and solve to get y 2x + 3 = y when x = 2 2(2) + 3 = y = y 7 = y

ratio– shows the relative sizes of two or more values 1:3 for every 2 boys there are 3 girls 1/4 are boys and 3/4 are girls 0.25 are boys and 0.75 are girls 25% are boys and 75% are girls

proportion– shows two ratios are equal 1/4 = 2/8 1/3 = 2/6

Solving proportions– “Cross multiply and divide through by the coefficient of the variable.”

coordinate plane – a horizontal number line (x- axis) and a vertical number line (y-axis) intersecting at an origin

ordered pair – a pair of numbers used to locate a point on a coordinate plane (2, 4) (-2, 3) The first number is x and tells you how far to move horizontally. The second number is y and tells you how far to move vertically.