# Which probability should use to approximate Binomail distribution?

As I know, we can appoximate binomial distribution by normal distribution and poisson distribution. But i don't clear it right and which better?

If the number of trials $n$ is limited and $np>10$, $n(1-p)>10$ use normal approximation.
If the number of trials goes to infinity while the product $np$ remains fixed use poisson approximation.