# How do you write an inequality and solve given "a number decreased by 8 is less than 21"?

Jan 25, 2017

#### Answer:

See the entire solution process below:

#### Explanation:

First, write the inequality.

Let's call the number we will be solving for $n$.

Therefore "a number decreased by 8" can be written as:

$n - 8$

"is less than 21" can be written as:

$< 21$

Putting this altogether gives:

$n - 8 < 21$

To solve for $n$ add $\textcolor{red}{8}$ to each side of the inequality which will solve for $n$ while keeping the inequality balanced:

$n - 8 + \textcolor{red}{8} < 21 + \textcolor{red}{8}$

$n - 0 < 29$

$n < 29$