Question

Is 1.313233 an irrational number

Answer 1

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.