**Frequently Asked Questions about Math**

**What is math?**

Math is a shortened form of the word *mathematics*. Mathematics is the study of numbers, quantities, structure, and space.

**What is mean?**

*Mean* is another word for *average*. Finding the mean is finding the central point in a set of numbers. To do this, add up all your values and then divide by the number of values you are given.

Ex. Find the mean of the set: {100, 98, 89, 92, 81}.

\(\large \frac{100+98+89+92+81}{5}=\frac{460}{5}=92\)

The mean of this set is 92.

**Watch a Video on Mean, Median, and Mode**

**What is mode?**

Mode is the most frequently occurring value in a set of data. It is possible to have more than one mode in a set.

Ex. What is the mode of the set: {11, 13, 21, 11, 19, 13, 11, 2}?

The mode is 11 because it is included three times in the set, while every other number is included only once or twice.

**What is range?**

Range is the distance between the largest and smallest values in a set of numbers.

Ex. Find the range of the set: {3, 11, 19, 1, 7}.

Largest Number: 19

Smallest Number: 1

19 – 1 = 18

The range of this set of numbers is 18.

**Watch a Video on Range**

**What is pi?**

Pi (π) is a Greek letter that represents the ratio of a circle’s circumference to its diameter. It is a never-ending number that cannot be written as a fraction, which means it is irrational. The approximate value of pi is 3.14.

**What is a function?**

A function is a relation between inputs and outputs in which every input has exactly one output.

You can tell if an equation is a function by graphing it and performing the vertical line test. To do this, imagine a vertical line is traveling across the *x*-axis. If at any *x*-value the line hits two different points, or *y*-values, your equation has failed the vertical line test and is not a function.

Ex. *y* = *x* is a function because for every *x*-value there is exactly one *y*-value.

**Watch a Video on Functions**

**What does ***product* mean?

*product*mean?

The product of numbers is the answer you get when you multiply those numbers together. In other words, a product is an answer to a multiplication problem.

Ex. What is the product of 3 and 4?

3 x 4 = 12

The product of 3 and 4 is 12.

**What is a variable?**

A variable is a symbol, typically an English or Greek letter, that represents an unknown value.

Ex. In the expression: \(x^{2}+2y-3z\), *x*, *y*, and *z* are all variables.

**Watch a Video on Variables**

**What is a constant?**

A constant is an unchanging number, or a value that does not change.

Ex. In the expression: \(3x^{2}+4y+5z\), 3, 4, and 5 are all constants.

**What is circumference?**

Circumference is the perimeter of a circle. It can be found by multiplying the circle’s diameter by pi, or by doubling its radius and then multiplying by pi.

*C* = π*d* or *C* = 2π*r*

Ex. What is the circumference of a circle with a radius of 5 cm?

*C* = 2π*r*

*C* = 2π(5 *cm*)

*C* = 10π *cm* ≈ 31.4 *cm*

**Watch a Video on Circumference**