How to work out the decimal between 2.65 and 2.66? with working out

-- There are an infinite number of different numbers between 2.65 and 2.66 .
To create one, just write ' 2.65 ' and add any quantity of any digits you want
after the ' 5 '.

--  If you want the number that's exactly in the middle between them, then
that's just the average of the two numbers.

The average of any two numbers is    (1/2) x (the sum of the numbers).

       (1/2) (2.65 + 2.66) = (1/2) (5.31)   =   2.655 .