A Glossary of Mathematical Terms - O
Obtuse
Octagon
An eight-sided polygon.
Odd number
An integer number that divided by 2 gives a remainder of 1.
One-to-one correspondence
A map where to not only to every element in the first set there corresponds one and only one element in the second set, but also vice-versa.
Operation
A specific process for combining quantities.
Opposites (Additive inverses)
Two numbers whose sum is 0.
Order of operations
The convention that detremines in which oder an expression is to be evaluated. A common mnemonic to help folks to remember the correct order for mathematical expressions is: Please excuse my dear aunt Sally. Parentheses, exponents, multiplication, division , addition, subtraction.
Ordered pair
A pair of objects in which the order is important.
Ordinal number
A number that describes order or position.
Ordinate
The second element in a coordinate pair.