Ranges are a powerful tool in Kotlin, and with some practice you will find the syntax intuitive. For this simple challenge, open the Kotlin REPL (Tools → Kotlin → REPL) and explore some range syntax, including the toList(), downTo, and until functions. Enter the following ranges, one by one. Before pressing Command-Return (Ctrl-Return) to execute the line and see the result, think about what you expect the result to be.