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?

(define (one? n) (= 0 (remainder (- n 1) 10)))
(define (ones l) (define (ones l) (foldl (λ (c e) (if (one? e) (+ c 1) c)) 0 l))

Lazy, and only works on n > 0