With the use of variables in mathematical expressions, you
can program the computer to do useful calculations for yourself. How about the tip in a restaurant? If you
know the cost of a meal $(meal)$, and decide what percentage to leave the server $(per)$, the tip will be
$tip=per/100\times meal$. With this, the total cost of the meal will be $total=meal+tip$. See if you
can finish the code below, and have a "tip calculator."

Type your code here:

See your results here:

Does your code work? Want to run it on your iPhone?

Here's your code:

- Use [Control]-[C] (Windows) or [⌘]-[C] (MacOS) to copy your code.
- Paste it using [Control]-[V] (Windows) or [⌘]-[V] (MacOS) into
this page
- Then click the "Use on iPhone" button that you'll see.