Rona has 4 packs of 12 glitter pens. She has 7 packs of 8 scented pens. She gives her friend a pack of glitter pens in exchange for a new pack of scented pens. How many pens does Rona have now?
A.92
B.104
C.100
D. 12
start with 4 * 12 = 48 glitter and 7* 8 = 56 scented
48 + 56 = 104 total to start
take away 12 glitter and add 8 scented
104 - 12 + 8 = 104 - 4
= ?