Solution 1

``````def multiply_by_two(x):
return x * 2
``````

# Function arguments

We're going to explore how to receive parameters and operate with them in your functions. In the editor you'll see a simple function that accepts just one parameter (named `x` in this case). This function's job is to multiply `x` by 2 and return the result. For example, if we pass 3 as the parameter, we're going to receive `3 * 2` as the result:

``````multiply_by_two(3)  # 6
``````

Parameters are matched by position. In this case `multiply_by_two` receives only one parameter (`x`), so when we invoke it passing the number `3`, it gets assigned to `x`.

Now go ahead and try implementing the `multiply_by_two` function by yourself.

### Test Cases

test five times two -

``````def test_five_times_two():
assert multiply_by_two(5) == 10
``````

test two times two -

``````def test_two_times_two():
assert multiply_by_two(2) == 4
``````
def multiply_by_two(x): pass # --- Testing --- # Use the code below for your own testing # by clicking the "Run Code" button. # After you're done, remove the lines below and "Submit Solution". two_times_two = multiply_by_two(2) three_times_two = multiply_by_two(3) five_times_two = multiply_by_two(5) print("2x2 = {}".format(two_times_two)) print("3x2 = {}".format(three_times_two)) print("5x2 = {}".format(five_times_two)) # --- Testing ---