# Math Vocabulary

Word Definition Examples
M   Magnitude The length of a vector
Matrix A rectangular arrangement of numbers, it uses big brackets to define the matrix. The size of a matrix is # of rows by the # of columns.
Maximum value - max The largest value a function can reach. for y = - x2 + 2 the maximum value is 2
Measures of central tendency Numbers that represent the whole set of data - usually the mean, median, and mode
Mean The sum of a set of numbers divided by the number of items - the average

for 1, 3, 4, 6 and 6

the mean is:
(1 + 3+ 4 + 6 + 6)/5 = 4

the median is the middle = 4

Median
statistics
The middle value in an ordered set - line up the numbers from smallest to largest and find the middle
Median
geometry
In a triangle, a line drawn from the midpoint of a side to the vertex opposite. Every traingle has three medians.
Midpoint The point that divides a line into two equal pieces. For the line with end points at A(x1,y1) and B(x2,y2), the midpoint is located at:
 x1 + x2 , y1 + y2 2 2
The midpoint of a line with ends at (2,5) and (4,7) is at (3,6)
Minimum value The smallest value a function can reach. for y  =  x2 + 5 the minimum value is 5
Mode The data item that occurs most frequently in a set of numbers. A set may have more than one mode. for 1, 3, 4, 6 and 6
the mode is 6
Mixed number A number written with a whole number part and a fractional part.

2 Ľ
mixed number

Multiplicative identity The number that multiples anything without changing its value.

1

a x 1 = 1 x a = a

Multiplicative inverse Two numbers that multiply to equal one. Also called the reciprocal. The reciprocal or inverse of a fraction is the fraction turned upside down ˝ and 2 are inverses because ˝ 2 = 1
Multiplication counting principle If there are m ways to make a first selection and n ways to make a second selection, then there are m x n ways to make the two selections If there are 3 kinds of crust and 6 kinds of topping, then there are 3 x 6 = 18 different pizza choices
Word Definition Examples
N    Natural logarithm Logarithm to the base e. The function y = ln x is the natural log. It is the same as y = loge x
Natural number The counting numbers - the first numbers learned by very small children
1, 2, 3, 4, 5, ...
Negation If a statement is represented by p, then the negation is not p. The opposite of a statement:
p - Today is Monday
not p - Today is not Monday.
Negative angle An angle formed by a clockwise rotation around the vertex.
Negative exponent An exponent that is used instead of the reciprocal a-3 = 1/a3
Negative square root - √ - √25 = - 5 is the negative square root of 25
N-gon A polygon with n sides. A polygon with 5 sides is a pentagon
A polygon with 42 sides is a 42-gon
Non-repeating decimal An irrational number approximated by a decimal. The exact value, if expressed as a decimal would never repeat and never end. √ 2 is approximately 1.414
Normal distribution A statistical frequency distribution that graphs in the shape of a bell curve
Word Definition Examples
O    Oblique triangle Any triangle that is not a right triangle
Observational data In statistics, data that is from seeing something happen or asking someone (doing a survey) about what happened.
Obtuse angle An angle that measures between 90 and 180 degrees

90° < x < 180°

Obtuse triangle A triangle with one obtuse angle One angle bigger than 90°
Odd Function A function graph whose axis of symmetry is both the x-axis and the y-axis. It must pass through the origin.

y = 5x3

Odd number Any number that has a remainder when divided by 2 . In Algebra, 2n + 1 can represent any odd number.
One-to-one function A function where the range elements (the y's) are used only once. y = 2x + 3 is one-to-one
Open interval An interval that does not include the endpoints (-4, 5) is the interval between -4 and 5
Operation An action performed on one or two numbers to produce a resulting number.
Operations are addition, subtraction, multiplication, division, square roots, and so on.

+, -, x, /, ÷, √

Opposites Additive inverses - they are the same distance from zero on the number line Two numbers that add to zero + 7 and - 7 are opposites
Opposite rays Two collinear rays that share the same endpoint and together form a straight line
Order of operations
1. do any operation inside grouping symbols, like parentheses, absolute values, square root signs or the numerator or denominator of a complex fraction
2. simplify terms with exponents
3. multiply and divide in order from left to right
4. add and subtract in order from left to right

PEMDAS

Ordered numbers Numbers that are arranged in order from smallest to largest or from largest to smallest 5 < 7 < 8.5
6 > 2 > -1
Ordered pair The location of a point on a coordinate axis (6, -1) is a point 6 units to the right and 1 unit down from the origin
Origin The place where the x axis and y axis intersect in a coordinate plane

(0, 0)

OrthocenterThe point in a triangle where the altitudes of the triangle intersect. Click here for an animated example of the orthocenter.
Orthogonal vectors Vectors that are perpendicular, meaning the angle between the two vectors is 90°
Orthographic drawing A drawing that represents a three dimensional object by showing separate drawings for the front, top and right side views
Outcomes The possible results of a probability experiment If you flip a coin, the possible outcomes are heads or tails
Comments, questions, or you just need some help? Send an e-mail to Mrs. Shearer Last Updated: 08/20/2010