N I O I P I Q I R I S I T I U I V I W I X I Y I Z

**A**I B I C I D I E I F I G I H I I I J I K I L I MN I O I P I Q I R I S I T I U I V I W I X I Y I Z

## O

An angle that is neither a right, acute or obtuse angle.

An angle whose measure is greater than 90° .

A triangle with an obtuse angle.

A polygon with 8 sides.

A whole number that is not evenly divisible by 2. (3, 5, 7, 9, etc…)

The ratio of the probability that an event will occur compared with the probability of it not occurring.

Addition, subtraction, multiplication, and division are the basic arithmetic operations.

The symbol that expresses the operation to be performed.

Two numbers that are located the same distance from 0 on the number line but in opposite directions. The sum of opposite numbers is 0.

Set of two numbers in which the order has an agreed-upon meaning, such as the Cartesian coordinates (

A set of rules for the order in which to solve mathematical problems. Start by multiplying and dividing, then adding and subtracting, always working within parentheses first. (Please Excuse My Dear Aunt Sally)

A number used to indicate place or position within a set or group.

The second element in a coordinate pair. When graphed in the coordinate plane, it is the distance from the x-axis. Frequently called the y coordinate.

The point (0,0) on a coordinate plane, where the x-axis and the y-axis intersect.

In probability, a possible result of an experiment.

**oblique angle**An angle that is neither a right, acute or obtuse angle.

**obtuse angle**An angle whose measure is greater than 90° .

**obtuse triangle**A triangle with an obtuse angle.

**octagon**A polygon with 8 sides.

**odd number**A whole number that is not evenly divisible by 2. (3, 5, 7, 9, etc…)

**odds**The ratio of the probability that an event will occur compared with the probability of it not occurring.

**operation**Addition, subtraction, multiplication, and division are the basic arithmetic operations.

**operator**The symbol that expresses the operation to be performed.

**opposites**Two numbers that are located the same distance from 0 on the number line but in opposite directions. The sum of opposite numbers is 0.

**ordered pair**Set of two numbers in which the order has an agreed-upon meaning, such as the Cartesian coordinates (

*x*,*y*), where the first coordinate represents the horizontal position, and the second coordinate represents the vertical position.**order of operations**A set of rules for the order in which to solve mathematical problems. Start by multiplying and dividing, then adding and subtracting, always working within parentheses first. (Please Excuse My Dear Aunt Sally)

**ordinal number**A number used to indicate place or position within a set or group.

**ordinate**The second element in a coordinate pair. When graphed in the coordinate plane, it is the distance from the x-axis. Frequently called the y coordinate.

**origin**The point (0,0) on a coordinate plane, where the x-axis and the y-axis intersect.

**outcome**In probability, a possible result of an experiment.