Which number is irrational?

0.14

4√

13

6√

Irrational number simply means it goes on and on without having a definite ending. So knowing that...

13 has and end

The square root of 4 is 2 which also has an end

0.14 has and end as well,
leaving the square root of 6, which is irrational. It keeps going on and on forever.

Another good example of an irrational number is pi, as it has no end (3.14159265...) Cheers!