One way to look at this is that 2/5 = 4/10, but depending on how well you understand fractions, you might not be able to compare 4/10 and 4/9.
To make it easier to see, we can find a common denominator:
2/5 = 18/45
4/9 = 20/45
No, 2/5 is not bigger than 4/9