center of a sphere  The given point from which the set of points of the sphere are at a given distance.

centi-  A prefix meaning 1/100.

centimeter  1/100 of a meter.

central angle of a circle  An angle with its vertex at the center of the circle.

certain event  An event with a probability of 1.

circle  The set of points in a plane at a certain distance from a certain point.

circle graph A graph in which information is represented using a circle that is cut into sectors to show values of a particular category. Also called a pie graph.

circumference  A circle's perimeter.

clockwise  The direction around a circle in which the hands on a clock usually move.

coefficient  The number by which a certain variable in a term is multiplied. Ex: 3xy (the 3 is the coefficient)

coincide  To occupy the same position.

column  A vertical line of objects in a rectangular array.

common denominator  A multiple of all the denominators in a problem.

Commutative Property of Addition   For any numbers a and b: a+ b = b + a.

Commutative Property of Multiplication   For any numbers a and b: ab = ba.

Comparison Model for Subtraction x - y is how much more x is than y.

composite number  Any positive integer exactly divisible by one or more positive integers other than itself and 1.

congruent figures  Figures with the same size and shape. Figures which are the image of each other under a reflection, rotation, or translation, or combination of these.

contraction  A size change with a magnitude  between 0 and 1.

conversion factor A factor by which one unit can be converted to another.

convex polygon  A polygon in which no diagonals lie outside the polygon.

coordinate graph  Displaying points as ordered pairs of numbers.

corresponding angles Any pair of angles in similar locations in relation to a transversal intersecting two lines.

corresponding sides  Any pair of sides in the same relative positions in two similar figures.

count  A number of particular things.

counterclockwise  The direction around a circle opposite from that in which the hands of a clock move.

counting unit The name of the particular things being tallied in a count.

cube A three-dimensional figure with six faces, each face being a square.

cubic units Units for measuring volume.

decimal notation  The notation in which numbers are written using ten digits and each place stands for a power of ten.

decimal system  The system in which numbers are written in decimal notation.

degree A unit of measurements equal to 1/360 of a complete revolution.

denominator  The divisor in a fraction, b in the fraction a/b.

diagonal of a polygon  A segment that connects two vertices of the polygon but is not a side of a polygon.

diameter of a circle A segment connecting two points of a circle and containing its center. The length of that segment.

difference The answer to a subtraction problem.

digit One of the ten symbols, 0 1 2 3 4 5 6 7 8 9, used to write numbers from zero to nine.

dimensions  The lengths of the sides of a rectangle. The number of rows and the number of columns in a rectangular array.

display The area on a calculator where numbers appear.

Distributive Property of Multiplication over Addition   For any numbers a, b, and x : ax + bx = ( a + b )x and x( a + b) = xa + xb. Also called distributivity.

Distributive Property of Multiplication over Subtraction   For any numbers a, b, and x : ax + bx = ( a - b )x and ( a - b ) = ax - bx. Also called distributivity.

dividend  The number in a quotient which is being divided. a is the dividend in a/b.

divisor (1) The number by which you divide in a quotient. b is the divisor in a/b.  (2)  A number exactly. Also called factor.