just a little joke with my friend

Normally, after a long day of work, i go with my friend to have a dinner in someone's university.
One day, i took ten yuan from my bag, and said to her, "Is it enough?" She didn't answer. Then, we went to the refectory, and picked out some food. When payed the bill, i was told it worth 12 yuan, my friend said, "ok, i'll pay the rest of your bill".hah
The next day, we still went to the refectory, i brought ten yuan and again said "Is it enough?" As you may know (have guessed), she would like to kill me.
hah it's just a little joke!

Really good! It's mostly prepositions and your meaning is clear. "As you may know" makes sense, but we would probably use another expresion.