## Defining Functions

To define your own function, use the `def` keyword, followed by the function name, which must follow the same rules for variable names. After the function name, put a pair of parentheses with variable names inside the parentheses. These variables are called parameters, and the values are passed into the function when using it. Example of a function that can add any two numbers:
```def sum(a, b):
result = a + b
```
Make sure to indent each line in the body of the function. If you try to use this function and print the result, you will get an error:
```def sum(a, b):
result = a + b

sum(5, 9)
print(result)

# Traceback (most recent call last):
#   File "main.py", line 5, in <module>
#     print(result)
# NameError: name 'result' is not defined
```
To access the value of the result variable, the function has to return the value using the `return` keyword. Example of returning the value and saving it in a variable:
```def sum(a, b):
result = a + b
return result

total = sum(5, 9)
print(total)
# 14
```

### Exercise 1 of 4

Finish the function.
```def multiply(a, b):
result = a * b
# return the value of result here

print(multiply(4, 2))
```

### Exercise 2 of 4

Finish the function.
```def subtract(a, b):
# find the value of a - b so you can return it
return result

print(subtract(4, 2))
```

### Exercise 3 of 4

Finish the function.
```def power(a, b):
# find the value of a raised to the power of b
# return the result

print(power(4, 2))
```

```print(divide(4, 2))