I often hear these mistakes made by German speakers who are learning English.
They say: We are four persons in my team.
There are a couple of things wrong with this.
Firstly, persons is only used in English in very formal or legal situations. We don’t use it in daily language. Instead just say people.
Secondly, don’t say ‘we are’, say ‘there are’.
So, the correct sentence is:
There are four people in my team.
Alternatively you can say:
There are four of us in my team.
Have fun learning English!
Louise