Find the number of instances for a service

Docker Engine Compose
1

Is there a way to find the “scaling” number of a service rather than relaying in the incremental naming of
the containers?

2

What is meant by scaling number?

3

I will be more clear.

I have a docker-compose project with 5 services and I am scaling some of then over different docker-hosts (i am using swarm clustering with consul) and i want to know at a given time the total number of the instances of a service.