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 =  x^{2} + 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: 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(x_{1},y_{1}) and B(x_{2},y_{2}),
the midpoint is located at:

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 = x^{2} + 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 ¼ 

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  ½ and 2 are inverses because ½ • 

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 = log_{e} 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/a^{3}  
Negative square root   √   √25 =  5 is the negative square root of 25  
Ngon  A polygon with n sides.  A polygon with 5 sides is a pentagon A polygon with 42 sides is a 42gon 

Nonrepeating 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 xaxis and the yaxis. It must pass through the origin. 
y = 5x^{3} 

Odd number  Any number that has a remainder when divided by 2 . In Algebra, 2n + 1 can represent any odd number.  
Onetoone function  A function where the range elements (the y's) are used only once.  y = 2x + 3 is onetoone  
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 

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) 

Orthocenter  The 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 
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