 # Variables in Python

In Python, information is stored in variables. We have already interacted with variables before when getting inputs from the user.
``````name = input()
surname = input()
print(name, '--', surname)``````
This program reads two inputs. It stores the first input in a variable called `name` and the second input in a variable called `surname`. In the case the person using the program inputs `Nikola` for the first input and then hit enter and put `Tesla` for the second input and then hit enter the `name` variable will store `Nikola` value in it and whenever printed will show `Nikola`, while `surname` variable will store `Tesla` value in it and whenever printed will show `Tesla`.

Variables can be used to store any type of information. They can store textual information as shown in the example above, they can store numbers, they can store collections, and other structures.
To store numeric values in variables we can do the following:
``````a = 10
b = 400
print(a, b, a * b)``````
The program will print `10 400 4000`.
This program stores `10` in a variable called `a`, `400` in a variable called `b`, and then prints their values along with the multiple of those two.

#### Challenge

Write a program that stores `-20` in a variable called `x`, `30` in a variable called `y`, and `100` in a variable called `z`. Print the result of the `x * y + z` expression.

So, we can use Python to do basic arithmetic operations and use it as a simple calculator.