On some stages, you will have unlimited operators, but on others, you will need to match them first. In addition to this, some stages will have tiles that change the target number, shuffle the board or randomly change their value.
There are 60 stages and thousands of randomly generated ones to choose from. The randomly generated stages can be rated (provided you complete it) so you can let other players know what fun levels there are to play.
Click here to download it from the Google Play store.