How does producing a number of eggs or young help in the survival of animal?

The more young or eggs an animal produces the more likely more of them will survive to adulthood and be able to breed, thus ensuring the survival of the species. It's a numbers game, for example: I tell you to guess a number between one and ten. Who is more likely to get it right, the person who only has one guess or the person who has 3 guesses. More guesses mean more chances to get the correct answer.