Setting score to moving variable

Solution 1:

To set the "RoomID" score equal to "Rooms" you would do this:

scoreboard players operation <player> RoomID = <player> Rooms

with <player> being a player either by username, target selector or *, to select all players.

To add one to the "Rooms" score you would do this:

scoreboard players add <player> Rooms 1

Again, <player> being a player either by username, target selector or *, to select all players.