What is the difference between rational numbers and fractional numbers?

Answer 1

A fraction is a ratio of two numbers. Fractions are typically ratios of integers (where the denominator is not zero), which makes them "rational." The root word of rational is ratio.

You could have pi/2, or sqr(2)/2, both of which are fractions that are NOT rational.

Answer 2

Rational numbers are equivalent to fractions whose numerators and denominators are integers. That need not be the case with just any fraction such as sqrt(2)/3 where the numerator is not an integer.