First of all, I was not studying math in English language, so I may use wrong words in my text.
Float numbers can be finite(42.36) and infinite (42.363636...)
In C/C++ numbers are stored at base 2. Our minds operate floats at base 10. 
The problem is -
many (a lot, actually) of float numbers with base 10, that are finite, have no exact finite representation in base 2, and vice-versa.
This doesn't mean anything most of the time. The last digit of double may be off by 1 bit - not a problem.
A problem arises when we compute two floats that are actually integers. 99.0/3.0 on C++ can result in 33.0 as well as 32.9999...99. And if you convert it to integer then - you are in for a surprise. I always add a special value (2*smallest value for given type and architecture) before rounding up in C for this reason. Should I do it in Python or not?
I have run some tests in Python and it seems float division always results as expected. But some tests are not enough because the problem is architecture-dependent. Do somebody know for sure if it is taken care of, and on what level - in float type itself or only in rounding up and shortening functions?
P.S. And if somebody can clarify the same thing for Haskell, which I am only starting with - it would be great.
UPDATE 
Folks pointed out to an official document stating there is uncertainty in floating point arithmetic. The remaining question is - do math functions like ceil take care of them or should I do it on my own? This must be pointed out to beginner users every time we speak of these functions, because otherwise they will all stumble on that problem.
The format C and C++ use for representing float and double is standardized (IEEE 754), and the problems you describe are inherent in that representation. Since Python is implemented in C, its floating point types are prone to the same rounding problems. 
Haskell's Float and Double are a somewhat higher level abstraction, but since most (all?) modern CPUs use IEEE754 for floating point calculations, you most probably will have that kind of rounding errors there as well. 
In other words: Only languages/libraries which choose to not base their floating point types on the underlying architecture might be able to circumvent the IEEE754 rounding problems to a certain degree, but since the underlying hardware does not support other representations directly, there has to be a performance penalty. Therefore, probably most languages will stick to the standard, not least because its limitations are well known.
Do Python and Haskell have the float uncertanity issue of C/C++?