I want to ask a friend of mine if there are enough people to play badminton tonight. Usually, there should be at least four persons to play a badminton game of double, but it's still at Chinese New Year and it's very cold and wet outside. There may not be enough four people to play the game, so do the following do the trick? Thanks.

Are there enough people to play the game? Do you need me to make up the number?
... Dou you want me to add up to the number?
... Do you expect me to make it four?
Do you have enough people without me?
Do you need me to make a fourth?
Do you need me to complete the foursome?
Thanks, Khoff.

Your versions sound excellent! To make sure, do the following sound natural?

Do you need me to complete the number (We all know the number is 4)?