additive inverse: The opposite (negative) of a number. Any number plus its additive inverse equals 0.
associative property: Grouping of elements makes no difference in the outcome. This is only true for multiplication and addition.
braces: Grouping symbols used after the use of brackets; signs { } used to represent a set.
brackets: Grouping symbols [ ], used after the use of parentheses.
canceling: In multiplication of fractions, dividing the same number into both a numerator and a denominator.
circumference: The distance around a circle; equals 2 × π × the radius or π × the diameter (C = 2πr or πd).
closure property: When all answers fall into the original set.
combinations: The total number of independent possible choices.
common denominator: A number that can be divided evenly by all denominators in the problem.
common factors: Factors that are the same for two or more numbers.
common multiples: Multiples that are the same for two or more numbers.
commutative property: The order of elements does not make any difference in the outcome. This is only true for multiplication and addition.
complex fraction: A fraction having a fraction or fractions in the numerator and/or denominator.
composite number: A number divisible by more than just 1 and itself.
cube: The result when a number is multiplied by itself twice.
cube root: A number that when multiplied by itself twice gives you the original number; its symbol is 3√.
decimal fraction: Fraction with a denominator 10, 100, 1,000, and so on, written using a decimal point; for example, .3 and .275.
decimal point: A point used to distinguish decimal fractions from whole numbers.
denominator: The bottom symbol or number of a fraction.
dependent events: When the outcome of one event has a bearing or effect on the outcome of another event.
difference: The result of subtraction.
distributive property: The process of distributing a number on the outside of the parentheses to each number on the inside; a(b + c) = ab + ac.
even number: An integer (positive whole numbers, zero, and negative whole numbers) divisible by 2 (with no remainder).
expanded notation: Pointing out the place value of a digit by writing a number as the digit × its place value. For example, 342 = (3 × 102 ) + (4 × 101) + (2 × 10).
exponent: A small number placed above and to the right of a number; expresses the power to which the quantity is to be raised or lowered.
factor (noun): A number or symbol that divides evenly into a larger number. For example, 6 is a factor of 24.
factor (verb): To find two or more quantities whose product equals the original quantity.
fraction: symbol that expresses part of a whole and consists of a numerator and a denominator; for example, 3/5.
greatest common factor: The largest factor common to two or more numbers.
identity element for addition 0: Any number added to 0 gives the original number.
identity element for multiplication 1: Any number multiplied by 1 gives the original number.
improper fraction: A fraction in which the numerator is greater than the denominator; for example, 3/2.
independent events: When the outcome of one event has no bearing or effect on the outcome of another event.
integer: A whole number, either positive, negative, or zero.
invert: Turn upside down, as in "invert 2/3 = 3/2."
irrational number: A number that is not rational (cannot be written as a fraction x/y, with x a natural number and y an integer); for example, √3 or π.
least common multiple: The smallest multiple that is common to two or more numbers.
lowest common denominator: The smallest number that can be divided evenly by all denominators in the problem.
mean (arithmetic): The average of a number of items in a group (the total items divided by the number of items).
median: The middle item in an ordered group. If the group has an even number of items, the median is the average of the two middle terms.
mixed number: A number containing both a whole number and a fraction; for example, 5½.
mode: The number appearing most frequently in a group.
multiples: Numbers found by multiplying a number by 2, by 3, by 4, and so on.
multiplicative inverse: The reciprocal of a number. Any number multiplied by its multiplicative inverse equals 1.
natural number: A counting number; 1, 2, 3, 4, and so on.
negative number: A number less than 0.
number series: A sequence of numbers with some pattern. One number follows another in some defined manner.
numerator: The top symbol or number of a fraction.
odd number: An integer not divisible by 2.
operation: Multiplication, addition, subtraction, or division.
order of operations: The priority given to an operation relative to other operations. For example, multiplication is performed before addition.
parentheses: Grouping symbols ( ).
percent or percentage: A common fraction with 100 as its denominator. For example, 37% is 37/100.
permutations: The total number of dependent choices.
place value: The value given a digit by the position of a digit in the number.
positive number: A number greater than zero.
power: A product of equal factors. 4 × 4 × 4 = 43, reads "four to the third power" or "the third power of four." Power and exponent are some× used interchangeably.
prime number: A number that can be divided by only itself and one. probability: The numerical measure of the chance of an outcome or event occurring.
product: The result of multiplication.
proper fraction: A fraction in which the numerator is less than the denominator; for example, 2/3.
proportion: Written as two equal ratios. For example, 5 is to 4 as 10 is to 8, or 5/4 = 10/8.
quotient: The result of division.
range: The difference between the largest and the smallest number in a set of numbers.
ratio: A comparison between two numbers or symbols; may be written x:y, x/y, or x is to y.
rational number: An integer or fraction such as 7/8 or 9/4 or 5/1. Any number that can be written as a fraction x/y with x a natural number and y an integer.
real number: Any rational or irrational number.
reciprocal: The multiplicative inverse of a number. For example, 2/3 is the reciprocal of 3/2.
reducing: Changing a fraction into its lowest terms. For example, 2/4 is reduced to 1/2.
rounding off: Changing a number to the nearest place value as specified; a method of approximating.
scientific notation: A number between 1 and 10 and multiplied by a power of 10, used for writing very large or very small numbers; for example, 2.5 × 104.
square: The result when a number is multiplied by itself.
square root: A number that when multiplied by itself gives you the original number; its symbol is √. For example, 5 is the square root of 25; √25 = 5.
sum: The result of addition.
tenth: The first decimal place to the right of the decimal point. For example, .7 is seven-tenths.
weighted mean: The mean of a set of numbers that have been weighted (multiplied by their relative importance or × of occurrence).
whole number: 0, 1, 2, 3, and so on.
