can be expressed as a fraction:
[tex]\frac{39}{50}[/tex]Therefore, it is a rational number
[tex]2.35[/tex]Can be expressed as a fraction:
[tex]\frac{47}{20}[/tex]Therefore, it is a rational number
However:
[tex]0.656656665[/tex]can't be expressed as a fraction, therefore, it is an irrational number