Function, variable and argument question

Hi,

So this question in Passing an Argument to a function is quite confusing for me. It goes as follows:

After your newly created returnValue function, create a new variable named echo. Set the value of echo to be the results from calling the returnValue function. When you call the returnValue function, make sure to pass in any string you'd like for the parameter.

The function will accept the string you pass to it and return it back (using the return statement). Then your echo variable will be set with what is returned, the results.

My answer was:

function returnValue(money){

return money;

} document.write(returnValue(“20”)); var echo = returnValue(“20”);

I typed this and it never passed. I cannot really see what I did wrong. I tried experimenting certain ways and eventually passed the task but it was through trial and error I didn't really get the concept nor the answer coherently understood.

Thanks in advance,