TABE Math key terms

The value a digit has because of its position in a number. In 4,702, the 7 means seven hundreds, while the 4 means four thousands.

A whole number that divides another whole number evenly, leaving no remainder. For example, 1, 2, 3, 4, 6, and 12 are all factors of 12.

The result of multiplying a whole number by any counting number. The multiples of 6 are 6, 12, 18, 24, and so on, continuing without end.

A whole number greater than 1 whose only positive factors are 1 and itself. Examples include 2, 3, 5, 7, and 11.

The smallest number that is a multiple of two or more given numbers. The least common multiple of 4 and 6 is 12, because 12 is the first multiple the two share.

Fractions that name the same amount even though their numerators and denominators differ. Multiplying or dividing the top and bottom by the same nonzero number produces an equivalent fraction, such as 1/2 and 4/8.

A ratio that compares a number to 100. Fifty percent means 50 out of every 100, which is the same as the fraction 50/100 or the decimal 0.5.

A comparison of two quantities by division. A ratio of 3 to 5 can be written as 3:5, as 3/5, or in words as three for every five.

A rate in which the second quantity is exactly one unit, such as 60 miles per 1 hour or $3.50 per 1 pound. Unit rates make it easy to compare different offers or speeds.

Any whole number that is positive, negative, or zero, with no fractional or decimal part. Examples are negative 7, 0, and 12; the number 2.5 is not an integer.

A small raised number that tells how many times the base is used as a factor. In five cubed, the exponent 3 means 5 times 5 times 5, which equals 125.

The agreed sequence for evaluating an expression: do parentheses first, then exponents, then multiplication and division from left to right, then addition and subtraction from left to right.

A letter or symbol that stands for an unknown or changing number in an expression or equation. In the expression 3x + 4, the letter x is the variable.

A mathematical phrase that combines numbers, variables, and operations without an equals sign. The phrase 5n minus 2 is an example; it can be evaluated for a given value but not solved.

A mathematical statement saying two expressions have the same value, shown by an equals sign, such as 2x + 5 = 13. Solving it means finding the variable value that makes the statement true.

A statement comparing two expressions that are not necessarily equal, using symbols such as less than, greater than, less than or equal to, or greater than or equal to. Reading x > 7 means x is greater than 7.

The number that multiplies a variable in a term. In 9y the coefficient is 9, and in negative 4ab the coefficient is negative 4.

Terms that have exactly the same variable parts, so their coefficients can be combined. The terms 3x and 7x add to 10x, but 3x and 3x squared are not like terms.

A rule that lets you multiply a number by a sum or difference by multiplying each part separately: a times the quantity b plus c equals ab plus ac. For example, 4 times the quantity x plus 3 equals 4x + 12.

An equation whose graph is a straight line and whose variables are raised only to the first power, such as y = 2x + 1. Its solutions form a straight pattern.

A measure of how steep a line is, found by dividing the vertical change by the horizontal change between two points on the line. It is often described as rise over run.

A rule that pairs every input value with exactly one output value. A function can be shown as a table, a graph, an equation, or a list of ordered pairs.

The distance around the outside edge of a flat figure, found by adding the lengths of all its sides. Perimeter is measured in linear units such as inches, feet, or meters.

The amount of surface a flat figure covers, measured in square units such as square inches or square centimeters. For a rectangle, area equals length times width.

The amount of space a solid figure occupies, measured in cubic units. For a rectangular box, volume equals length times width times height.

The distance around a circle, calculated as pi times the diameter or as two times pi times the radius. It plays the same role for a circle that perimeter plays for a polygon.

An angle that measures exactly 90 degrees and forms a square corner. The two sides that meet at a right angle are perpendicular to each other.

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

A rule for right triangles stating that the square of the hypotenuse equals the sum of the squares of the two shorter sides, written as a squared plus b squared equals c squared. It is used to find a missing side length.

Changing a measurement from one unit to another without changing the actual amount, such as rewriting 3 feet as 36 inches by multiplying by 12 inches per foot.

A table that lists categories or values and records how often each one occurs. The counts can be used to find totals, build graphs, or compare groups.

A graph that uses rectangles of different heights or lengths to compare counts across categories. The bars are usually separated by small gaps to show the categories are distinct.

A circle divided into slices that show what part of a whole each category represents. All the slices together must equal 100 percent of the data.

A graph that plots points for paired data to show whether two quantities are related. Points rising from left to right suggest a positive relationship between the variables.

The average of a data set, found by adding all the values and dividing by how many values there are. Very high or very low values can pull the mean up or down.

The middle value of a data set once the values are arranged in order from least to greatest. With an even number of values, the median is the mean of the two middle values.

The value that appears most often in a data set. A set can have one mode, more than one mode, or no mode at all if every value occurs equally often.

A measure of the spread of a data set, found by subtracting the smallest value from the largest value. It shows how far apart the extremes of the data are.

A number from 0 to 1 describing how likely an event is, often written as the number of favorable outcomes divided by the total number of possible outcomes. Zero means impossible and one means certain.

A group chosen from a larger population so that every member has an equal chance of being selected. Results from a random sample are more likely to represent the whole population fairly.