And in another year, those 5 cats can produce a total of at least 40 more cats. Those 40 reproduce, and so on.
SPAY AND NEUTER YOUR ANIMALS. It's no fun watching them die in a shelter because people think it's so cute to have kittens and puppies - 'cause there are not enough homes for all of them!
The responsible thing for you to do now is to spay/neuter each one (including mama) and get their shots before you give them away - that way you ensure no more unwanted babies. Contact a low cost place - even so, it will be expensive - but that's the burden you now face because you didn't spay mama.
And keep her in the house - cruel people are everywhere - you don't want to find her tortured and dead or ripped to pieces by a dog running loose or run over by a car or poisioned by a neighbor who doesn't think, she's all that cute crapping in their yard and climbing on their car. All of which happens on a daily basis in this country - hell, in my city.