It seems like what you need to do is simplify 676/260.
You can simplify it by dividing the top and the bottom by the same thing, until there's nothing left to evenly divide (divide with no remainder).
So for 676/260 the top and bottom can both be divided by 2:
676/260 =
(676/2)/(260/2) =
338/130
And for 338/130 the top and bottom can both be divided by 2 as well:
338/130 =
(338/2)/(130/2) =
169/65
And finally, for 169/65 the simplest form can be found by dividing both the top and the bottom by 13:
169/65 =
(169/13)/(65/13) =
the answer.