If you roll a number cube 72 times, how many times do you expect to roll a 6?

You would expect to roll a 6, 12 times. You get this answer by dividing 72 (the number of rolls) by 6 (the number of faces on the cube), then that tells you the number of times you can expect to roll each number. Not just a 6.

U would roll a 6 twelve times