Power Builder

96,97,98,99,100,101,102,103,and 104  =

Each of the first 4 terms written in reverse order and paired with the last 4 terms will produce a sum of 4(200)

Adding the middle term - 100 - produces   4(200) + 100  = 800 + 100   = 900

or do this: 96 + 97 + 98 + 99 + 100 + 101 + 102 + 103 + 104 = 900