My first attempt at Clojure. Suggestions/criticism welcome.

calculate_change.clj

(defn calculate-change
  ([paid cost] (make-change paid cost 0))
  ([paid cost denomination-index]
    (let
      [
        currency-values [
          [:hundreds 10000]
          [:fifties   5000]
          [:twenties  2000]
          [:tens      1000]
          [:fives      500]
          [:ones       100]
          [:quarters    25]
          [:dimes       10]
          [:nickels      5]
          [:pennies      1]
        ]
      ]
      (if
        (>= denomination-index (count currency-values)) {}
        (let
          [
            denomination (currency-values denomination-index)
            amount (int (/ (- paid cost) (last denomination)))
            value (* amount (last denomination))
          ]
          (conj
            {(first denomination) amount}
            (make-change (- paid value) cost (+ denomination-index 1))
          )
        )
      )
    )
  )
)