Question

I have to find how many brownies I MADE IF MY SISTER TOOK 1/2, MY BROTHER TOOK 2/3 AND MY DAY TOOK 1/2 AND ALL I HAVE LEFT IS SIX BROWNIES HOW DO I SHOW HOW MANY EACH PERSON TOOK AND WHAT KINDA OF MODELS CAN I USE TO SHOW THE TAKING AWAY OF BROWNIES