Each - .

Edge - .

Element of a set - An item in a list (set). Usually listed in a predefined order. Duplicate elements are generally eliminated.

Ellipse - .

Empty set - .

Endpoint - A point which terminates a line segment or ray.

Entire - All. Whole. 100 percent.

Equal - Having the same value or some other quality. See equivalent.

Equation - A statement of equality. Two expressions connected by an equal sign. Any operation may be performed on one side (member) of an equation, provided that: if the operation affects the value of the member expression (and not just the form, as with the distributive property), then it must be performed equally on both members; the operation must be legal for all members on which it is to be performed.

Equiangular - Having congruent angles (angles of equal measure).

Equiangular triangle - A triangle with three congruent angles (angles of equal measure). Each angle has a measure of 60 degrees. An equilateral triangle.

Equidistant - Having every point on a given figure or defined part of a figure the same distance from a given reference point or another figure.

Equilateral - Having congruent sides (sides of equal length).

Equilateral triangle - A triangle with three congruent sides (sides of equal length). An equiangular triangle.

Equivalent - See equal.

Equivalent fractions - Fractions which have the same value. Fractions which reduce to the same lowest terms. Fractions whose cross-products are equal. See proportion, ratio.

Estimate - .

Even number - A number which is divisible by two. When divided by two, there is no remainder; the answer (quotient) is a whole number (integer). An even number ends in 0, 2, 4, 6 or 8. See Odd number.

Exactly - Having a zero remainder. See divisible.

Exponent - The part of an expression showing the number of times (power) a factor is to be used in a multiplication. (Not the number of multiplications, which is one less.)

Expression - .

Extract - .

Last updated 6/2/97 - 4/13/2000.