why the float number is not perfectly stored in computer??

Question

float

Answer 1

the computer stores only a certain number of digits. Because of that, values like 1/3 or 2/3 couldn't be stored exactly.
1/3 = 0.33333333...

Answer 2

why the computer store only a certain no of digits?

Answer 3

because otherwise it would have to have infinite memory. But it can't because of how it is designed.
And before you ask why : it's designed like that because it can't use efficiently more digits for a number