fun add(n) x = x + n;
fun del(n) x = x - n;
fun mlt(n) x = x * n;

fun manipulate_one(k,[],action) = []
|   manipulate_one(1,l1,action) = (action (hd l1)) :: tl l1
|   manipulate_one(k,l1,action) =
        if k >= 1 then
            hd l1 :: manipulate_one(k-1, tl l1, action)
        else
            l1;