2.2 numbers less than 10

Because haskell wants to break functions into the compositions of simple functions, break it down into simple problems. Just as before, we're going to work on the smaller numbers, such as from 0 to 9, which will introduce more list notation in Haskell.

unitStrings :: [String] -- Define as a list of strings
unitStrings = ["zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine"] -- idx corresponds with end digit 

units :: Int -> String
units u = unitStrings!!u -- Whoa!

For accessing an element in a list in Haskell, you need to be excited, with !! acting as the accessor function:

(!!) :: [a] -> Int -> a

Since, well, accessing from a list is a function now. And, since Haskell is sane, lists are zero indexed.