http://blog.youkuaiyun.com/luozhuang/archive/2011/03/09/6234579.aspx 挺好玩的,也来写一下: (define (problem1 i) (if (< i 10) i (problem1 (+ (* (truncate (/ i 10)) 2) (modulo i 10))))) (problem1 88888888) ;=> 8