TSIA2 Math key terms

A comparison of two quantities by division, often written as a to b, a:b, or a/b. It describes how much of one quantity exists relative to another.

An equation stating that two ratios are equal. Solving a proportion usually means finding a missing value by cross-multiplying or by using equivalent fractions.

A rate in which the second quantity is one unit, such as miles per one hour or cost per one item. It makes comparing speeds, prices, or other rates easier.

A ratio that compares a number to 100. For example, 35% means 35 out of every 100, which is the same as the decimal 0.35.

The amount a value increases or decreases, divided by the original value, then written as a percent. It compares the size of a change with the starting amount.

The distance of a number from zero on the number line, which is always zero or positive. Both 7 and -7 have an absolute value of 7.

The agreed sequence for evaluating expressions: parentheses, exponents, multiplication and division from left to right, then addition and subtraction from left to right. It prevents different people from getting different answers.

A way to write very large or very small numbers as a number between 1 and 10 multiplied by a power of 10. For example, 4,500 = 4.5 × 10^3.

A fraction equal to 1 that relates two units, such as 12 inches over 1 foot. Multiplying by it changes units without changing the actual amount.

A letter or symbol that stands for an unknown number or a value that can change. Variables let expressions and equations describe general relationships.

A mathematical phrase that combines numbers, variables, and operations, with no equals sign. It can be simplified or evaluated but is not solved like an equation.

A mathematical statement that two expressions are equal, shown with an equals sign. Solving it means finding values of the variable that make the statement true.

An equation whose graph is a straight line, often written y = mx + b or ax + by = c. Its variables have no exponent other than 1.

The steepness of a line, calculated as rise over run or change in y divided by change in x. It tells how much y changes for each one-unit increase in x.

The point where a line crosses the y-axis, written as (0, b). In y = mx + b, it is the output when the input x equals zero.

Two or more linear equations considered together. A solution is an ordered pair that satisfies all of them at once, found by graphing, substitution, or elimination.

A statement comparing two expressions with <, >, ≤, or ≥. Its solution is a range of values rather than a single value, often shown on a number line.

A rule that assigns exactly one output value to each input value. Tables, graphs, and equations can all represent functions.

An equation of degree two, usually written ax² + bx + c = 0 with a not equal to zero. Its graph is a parabola, and it can have two, one, or no real solutions.

The total distance around the outside of a two-dimensional figure, found by adding its side lengths. It is measured in linear units such as inches or meters.

The amount of surface a two-dimensional figure covers, measured in square units. Formulas differ by shape, such as length times width for a rectangle.

The distance around a circle, calculated as pi times the diameter or as 2 times pi times the radius. It is the circle's perimeter.

The amount of space a three-dimensional solid occupies, measured in cubic units. It is often found by multiplying a base area by a height or depth.

The total area of all the outer faces or surfaces of a three-dimensional solid, measured in square units. It is like the amount of wrapping needed to cover the object.

In a right triangle, the square of the hypotenuse equals the sum of the squares of the other two sides: a² + b² = c². It finds a missing side length.

Figures that have the same shape but not necessarily the same size. Their corresponding angles are equal, and their corresponding side lengths are proportional.

Two angles whose measures add to 90 degrees. They can be adjacent or separate, as long as their total equals a right angle.

A grid formed by a horizontal x-axis and a vertical y-axis that meet at the origin. Points are located with ordered pairs (x, y).

The arithmetic average of a data set, found by adding all values and dividing by the number of values. Very large or very small values can pull it up or down.

The middle value when a data set is ordered from least to greatest. With an even number of values, it is the average of the two middle values.

The value that appears most often in a data set. A set may have one mode, more than one mode, or no mode at all.

The difference between the greatest and least values in a data set. It gives a quick measure of how spread out the data are.

A number from 0 to 1 that describes how likely an event is. It can be found by dividing favorable outcomes by total equally likely outcomes.

A graph of ordered pairs on a coordinate plane that shows the relationship between two numerical variables. Patterns may suggest positive, negative, or no correlation.

A straight line drawn through a scatter plot that best models the overall trend of the data. It can be used to make predictions.

A data value that is much larger or much smaller than the rest of the values. It can strongly affect the mean and other statistics.