Bakers math

Hello I am trying to figure out the steps I need to take to answer this question and I'm having a tough time with it. If I have 100 grams of starter and I know it is an 80% hydration starter, how do I determine how much flour is in the starter?I actually know the answer (54g flour 44g water), I just dont know how to arrive at it for myself. I am looking for the steps to take