Thanks everyone! I spoke to mom last night about the hitting and she looked at her daughter and said: "we don't hit". She then turned around and hit her mom. All mom did was smirk.

I was going to wait until Friday to give her notice, but today her daughter high pitched screamed from 9 am until 12:30 pm. She also continued to run in the kitchen where she knocked over my 15-month-old and he put his tooth right through his tongue. She displayed no empathy, as he was bleeding everywhere and continued running and laughing. I put her on a time-out and she started high pitched screaming and laughing again. After 15 more minutes of the screaming I called their mother and there was no answer. Mind you every child in my care this morning is upset with her yelling. Terrible day!