Two possible rational numbers between -2/3 and 1/2 are:

How many prime numbers are there between 1 and 50?

How many numbers between 11 and 90 are divisible by 7?

How many numbers between 100 and 500 are divisible by 4, 5 and 6?

How many numbers between 200 and 600 are divisible by 4, 5 and 6?

The difference between the squares of two numbers is 256000 and the sum of the numbers is 1000. The number are