Here are three rational numbers between -1 and -2:

• -1.25 which can be expressed as the fraction -5/4
• -1.5 which can be expressed as the fraction -3/2
• -1.75 which can be expressed as the fraction -7/4

A rational number is any number that can be expressed as a fraction where both the numerator and denominator are integers. Because there are an infinite amount of numbers between any two numbers, there are also an infinite amount of rational numbers between -1 and -2.