Tom and his brother each have to clean 12 of the playroom. Tom’s friend offered to clean 14 of Tom’s part. What fraction of the room is left for Tom to clean?

Aliter of water contains about 3.35 x 10^25 molecules. a certain river discharges about 2.9x 10^8 l of water every second. about how many molecules does the river discharge every minute? write your answer in scientific notation