What's a REPL?
You're looking at a JavaScript R.E.P.L. That stands for:
It's a way of interacting with a JavaScript engine. When you type in some
JavaScript code, the JavaScript engine reads it, evaluates it,
prints the result, and loops back, waiting again for you to give
it another instruction. Pressing the "enter" key lets the R.E.P.L. know
you're done typing and ready for it to go to work.
You don't need to know a thing about JavaScript to use this REPL. For now,
think of it as a fancy calculator. Give it a try! Use the +, -, *, and /
operators to do a little arithmetic.
Does it follow the order of operations? Try an experiment to find out.
What else can you think to try? Take note of anything that surprises or
perplexes you.
When you're ready to move on, click the ✓ button.