# Using not to Determine Range

**00:00**
Here’s another example of when you might use `not`

in an `if`

statement condition. Determining if a number is inside or outside a particular range of values is a very common task.

**00:15**
And writing a condition to see if a number is inside a range is pretty straightforward. You usually use a compound inequality using the word `and`

. To be in the range `20`

to `40`

, including the end point of `20`

, a number has to be at least `20`

and at the same time, less than `40`

.

**00:54**
And `30`

is indeed inside that range. This type of comparison is so common that there are other ways to write this condition. And you’ll see at least one of those in an upcoming lesson.

**01:06**
But now suppose you want to check if a number is outside that range. What would that condition look like? Well, the easiest way is to just put `not`

in front of this condition.

**01:27**
If you say `not`

followed by the previous condition, this will now be `True`

when a number is outside of that range. Remember you want to do the `and`

first, so that part of the condition has to be put in parentheses.

**01:51**
And `50`

is outside of that range. Next, you’ll see how `not`

can be used in the condition for `while`

loops.

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