Doing an experiment to find the solubility of calcium carbonate in 100 ml of water. The experiment is using water temp 20 degrees and 35 degrees celcius and also using slow and fast stirring speeds. How many variables are being used?

Is the amount of water a variable? No.
You are using two temperatures. Is that a variable? Certainly.
You are using two stirring speeds. Is that a variable? Careful.
Note the correct spelling of Celsius.

The question is set up like a chart with the two different temperatures and the two different stirring speeds. Therefore, the experiment is 20 degrees at slow stirring speed and at fast stirring speed. Then 35 degrees at slow stirring speed and fast stirring speed.