19 - you would divide number of beads by beads per bracelet to get number of bracelets
blue = 258/6 = 43
silver = 428/9 = 47.56, round down because we're looking at complete bracelets = 47
rose = 102/3 = 34
white = 258/7 =36.86, round down again = 36
20 - they can make 43 + 47 + 34 + 36 = 160 bracelets before they run out, and they will run out of rose first since it has the smallest number of bracelets
21 - multiply num of beads by num of bracelets for each color and add them up
