Average
Three types of averages are the mean, mode and median. The weekly salaries of six employees at McDonalds are $140, $220, $90, $180, $140, $200. For these six salaries, find: (a) the mean (b) the median (c) the mode.
List the data in order: 90, 140, 140, 180, 200, 220
Mean: 90+ 140+ 140+ 180 + 200 + 220 = 
6
Median: 90,140,140,180,200,220
The two numbers that fall in the middle need to be
averaged. 140 + 180 = 160
2
Mode: The number that appears the most is 140
A magic square is an arrangement of the numbers from 1 to n^2 (n-squared) in an nxn matrix, with each number occurring exactly once, and such that the sum of the entries of any row, any column, or any main diagonal is the same. It is not hard to show that this sum must be n(n^2+1)/2.