If I can write your number as a fraction with whole numbers
on top and bottom, then your number is rational.
1.313233 = 1,313,233 / 1,000,000 yay !
I did it ! Your number is rational.
Here's a hint that will give you the rational/irrational answer
to probably 95% of the examples you ever see:
Any number that you can write down on paper, completely,
using digits (and a decimal point or fraction bar if necessary)
is always rational.