# How do you use this symbol in an equation? #in#

##### 1 Answer

See below:

#### Explanation:

The symbol *element*) lies within a set.

For instance, I can use it to say something like *within the set of rooms in my house, there is a kitchen, which I can write as:

While the symbol

For instance, what if I want to have an equation that tells me how much it will cost to talk to a lawyer. The lawyer charges $100/hour, and so I can write:

and I can add some symbols and write it as :

We don't want to deal with fractional hours - we only want the natural numbers, so to limit the type of number we substitute in for