The Big Nerd Ranch Swift - Ch.20 Bronze Challenge

There is no description of challenge. Becaouse of license.

When I use a header “class someName…” in code block for some code, that means the following code is within the scope of the class named ‘someName’.

I added minus token and implemented related works as plus did. I think it would be good calculation model when you make caculation iOS app. See the code

code