18. Mary had a jar of jelly beans 2/3 full. She divided them equally between herself and a friend. How much did each friend get?

Mary divided her jelly beans into 2 equal pieces.

Invewrt and multiply. The 2 to the right of the division sign has an invisible denominator of 1, so when you invert it you get 1/2

Each of them would get 1/3 of a jar of jelly beans