Today we learned about factorial notation into perms/coms(permutation/combination). Permutation means-an ordering of objects in which order matters(ie. makes a diffrence) ex. phone number, locker permutation, postal codes, etc. a combination means- an ordering of objects in which ORDER doesn't matter, ex. card hands, pizza toppings, committee membership(all members the same). the formula for perutation is nPr and the formula for combination is nCr which means n objects combined r at a time nCr=n!/(n-r)!*r!