text: hard homework math help? the mean of 5 numbers is 27. four of the numbers are 24, 33, 27 and 31. what is the fifth number? mean means average  and if you multiply the number of numbers (5) by the avg (27), you get the sum  then you take the sum (135) and subract the other 4 to get the final one!  (to check, add them all up, and they should eqaul 135, and the avg shoiuld be 27)