Function literals used inline in Go language

I think this is a feature that is worth showcasing. While the language in my comments may need a good bit of improvement, I think this is an important and useful feature to learn.
If you don't mind, change the "Called with args (10, 2)" and make it "Called with args 10 and 2"
Also, could you add a comment: `// => ____` where `_____` is the output of what this function call with do? Having the output in a comment here will make it much easier to understand what the functions do while reading the doc.