Most types of worms can multiply pretty rapidly and reproduce rapidly as well.
For example a red wiggler worm can multiply and produce two to three cocoons per week which is pretty fast when it comes to reproduction.
Also each cocoon that a worm produces has 3 hatchlings so that's quite a few worms produced by one worm.
So that means that a worm can multiply and produce around 12 worms per week or around 48 worms per month which is pretty impressive when you think about it because of the size that a worm is.
Worms are good for the soil as well and can help you keep your garden healthy by keeping the soil turned over so worms are pretty beneficial to the earth and our gardens.