c.scm

(define fact
    (lambda (n)
        (if (<= n 1)
            1
            (* n (fact (- n 1)))
        )
    )
)

(define perms
    (lambda (n r)
        (/ (fact n) (fact (- n r)))
    )
)

(define choose
    (lambda (n r)
        (/ (perms n r) (fact r))
    )
)

(display (choose 10 4))
(newline)