Clojure: Increment first element of every vector in list

I have a list of vectors like this:

([4 0] [4 2] [2 1] [4 1])

How can i increment the first element of every vector by a certain value X ?

desired output:

([5 0] [5 2] [3 1] [5 1])

This is my current approach, but i think i could be much simpler:

(defn shiftVector [oldVector number]   (map vector      (map #(+ (first %) number) oldVector )      (map  #(second %) oldVector)))