# How do you define a variable and write an expression for each phrase: one-third of the total of nine times a number and twenty one?

##### 1 Answer

Jul 25, 2017

#### Answer:

#### Explanation:

You don't need to "define" a variable, if that is what you mean. A variable can be any letter -

One third of the **total of** states that the "nine times a number and twenty one" comes *before* the one-third.

Since we defined "a number" to be

The "total of" is telling us to take the sum of

And then it is asking us to take

is

Therefore we get