She began to yell at her tablet game which got her a warning.
Did she say why she was yelling?
I asked her what she is doing and she told me this.
It may seem that children lose their temper at the oddest things. While it's okay to get frustrated, they have to be taught that yelling doesn't alleviate the situation.
She is just a kid and should learn to manage her temper.
Kids can learn to manage their temper when a responsible adult helps them to understand how to do so. If you think she needs to learn this skill, you should find a way to help her.