ISEE Math Achievement key terms

A whole number that can be positive, negative, or zero, with no fractional or decimal part. Examples include -7, 0, 4, and 250.

Any number that can be written as a fraction with integers in the numerator and denominator, where the denominator is not zero. Decimals that terminate or repeat are rational.

A real number that cannot be expressed as a fraction of two integers. Its decimal form goes on forever without repeating, as with pi or the square root of 2.

The distance of a number from zero on the number line, always zero or positive. Written with vertical bars, so the absolute value of -6 is 6.

A straight line on which every point matches a number, with zero in the middle, positives to the right, and negatives to the left. Used to compare values and show distances.

A statement comparing two quantities that are not necessarily equal, using symbols such as less than, greater than, less than or equal to, or greater than or equal to.

The agreed sequence for evaluating expressions: grouping symbols first, then exponents, then multiplication and division left to right, then addition and subtraction left to right.

A small raised number showing how many times a base is used as a factor. In 5 cubed, the exponent 3 means 5 times 5 times 5.

A number that, when multiplied by itself, produces a given value. The square root of 49 is 7 because 7 times 7 equals 49.

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

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

The result of multiplying a given whole number by any whole number. The multiples of 4 include 4, 8, 12, 16, and so on.

The largest whole number that divides two or more given numbers evenly. For 18 and 24, the greatest common factor is 6.

The smallest nonzero whole number that is a multiple of two or more given numbers. For 6 and 8, the least common multiple is 24.

A comparison of two quantities by division, often written with a colon or as a fraction. A ratio of 3 to 5 can be written 3:5 or 3/5.

An equation stating that two ratios are equal. Cross-multiplying a proportion such as 2/3 equals 8/12 confirms the two ratios match.

A rate expressed per one unit of the second quantity, found by dividing. Driving 150 miles in 3 hours gives a unit rate of 50 miles per hour.

A ratio out of 100, shown with the percent symbol. Twenty-five percent means 25 out of every 100, or one quarter of the whole.

The amount a value grows, stated as a percent of the original value. Find it by dividing the change by the original amount and multiplying by 100.

The amount a value shrinks, stated as a percent of the original value. Divide the drop by the starting amount, then multiply by 100.

A letter or symbol standing for an unknown or changing number in an expression or equation. In 4x plus 7, the letter x is the variable.

The number multiplied by a variable in a term. In the term 9y, the coefficient is 9; in -3x, it is -3.

A combination of numbers, variables, and operation symbols that does not contain an equals sign. For example, 3x plus 2y minus 5 is an expression.

A mathematical sentence stating that two expressions have equal value, shown with an equals sign. Solving it means finding values that make the statement true.

An equation in which every variable appears to the first power, so its graph is a straight line. An example is 2x plus 5 equals 13.

All values of the variable that make an equation or inequality true. For x squared equals 9, the solution set is 3 and -3.

A measure of how steep a line is, equal to rise over run, or the change in y divided by the change in x between two points.

The point where a graph crosses the vertical y-axis, occurring where x equals zero. In y equals 3x plus 4, the y-intercept is 4.

A rule pairing each input with exactly one output. A table where one input gives two different outputs does not describe a function.

The total distance around the outside of a flat figure, found by adding the lengths of all its sides. Perimeter is measured in linear units.

The amount of flat surface a shape covers, measured in square units. For a rectangle, multiply length by width.

The amount of space a three-dimensional solid occupies, measured in cubic units. For a rectangular box, multiply length, width, and height.

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

The distance from the center of a circle to any point on its edge. It is exactly half of the diameter.

The distance across a circle through its center, equal to twice the radius. It is the longest chord of the circle.

The average of a data set, found by adding all values and dividing by how many values there are. The mean of 2, 4, and 9 is 5.

The middle value of a data set arranged in order. If there is an even number of values, it is the mean of the two middle values.

The value that appears most often in a data set. A set can have one mode, several modes, or no mode at all.

A number from 0 to 1 describing how likely an event is, found by dividing favorable outcomes by total equally likely outcomes.