Translation:That is not going to reduce the number.
I do not see how what you say is correct. "ir" can translate to: go , be , head , walk , pass , pursue , fit , run away , pass by , get at , run for , run after , chase after , be behind , suit , lead , follow
And "will" is not even related to these verbs.
And English, "will," translates to Spanish as: querer , legar , dejar en testamento , ordenar , lograr por fuerza de voluntad , sugestionar
And "ir" is not included.
Because in this instance you can't really cut down on a number. In this example, think of it as an offer..."What if I throw in a washing machine?"--"Well, that is not going to reduce the number!".
Also, reducir can be used to "cut down" in dietary terms. For example, "I am going to cut down (reduce) salt intake".