Scheme/DrRacket

How do I write a function that takes any integers in a list and produces the number of values in the list whose one's digit (i.e. the least significant or rightmost digit) is 1. For example,
(ones (list 82 231 1 22 1000)) => 2?


ones :: Integral a => [a] -> Int
ones = foldr step 0
    where step x z | x `mod` 10 == 1 = succ z
                   | otherwise = z