The sum of all odd #'s between 2 and 30.

  Odd numbers between 2 and 30 would be the
sequence:

3, 5, 7, ....,
29 

 The sum of odd numbers from 1 to n, where n is an odd
number, formula is:

1 +3 + ....+ 2n-1 =
n^2

then,

1 +3+....+ 2(15)-1 =
(15)^2

by subtracting 1 from both
sides:

3+5+...+ 29 = (15)^2 - 1 =
225-1=224

the sum of the odd numbers between 2 and
30 equals 224