To find a rational number between any two numbers such as r and s, you can add r and s and divide the sum by 2, ie.., (r+s)/2 lies between r and s.
Let r = 1 and s = 2. Find 6 rational numbers between 1 and 2.
We literally want rational numbers i.e., fractions between 1 and 2. The resultant fraction must be greater than 1 and less than 2.