Also, because there is only one expression in the method body, we drop the braces and put the entire method definition on one line.

Use the +, -, *, / symbols and parentheses to do a simple equation.

Well, the bracket notation means you can index into this variable.

The curly braces ensure that everything is logically clustered where it should be.

Note that each argument list is surrounded by parentheses and the arguments are separated by commas.