Which fraction should be added to:
1/(2 Ã— 3) + 1/(3 Ã— 4) + 1/(4 Ã— 5) + ....... + 1/(25 Ã— 26)
so that the result is equal to 1?  Choose the correct answer.
A) 5/13  B) 6/13  C) 7/13  D) 8/13  E) 9/13
The given expression   = 1/(2 Ã— 3) + 1/(3 Ã— 4) + 1/(4 Ã— 5) + ...... + 1/(25 Ã— 26)   = (1/2 - 1/3) + (1/3 - 1/4) + (1/4 - 1/5) + .......... + (1/25 - 1/26)   = 1/2 - 1/26 = 12/26   Thus, the fraction we should add = 1 - 12/26 = 7/13   The answer is 7/13.
<result>C</result>
Which fraction should be added to:
1/(2 Ã— 3) + 1/(3 Ã— 4) + 1/(4 Ã— 5) + ....... + 1/(25 Ã— 26)
so that the result is equal to 1?