To expand on this, the imprecision arises the moment you write 0.1 (decimal) in source code and the compiler converts it to binary; the arithmetic itself is (mostly) exact. So as long as you use numbers that look "good enough" in base-2, floats behave very reasonably. The constantly made assumption that floats are imprecise is, in this sense, a user error -- the user shouldn't have used decimals.