Okay, so imagine you have a bunch of pieces of paper that have numbers on them. These numbers are really important because they tell you how much money you have.
Now, sometimes you need to give some of your money to other people or buy things. But you can't just give them a whole piece of paper with your entire balance on it, that wouldn't be safe!
So what you do is you take a tiny piece of that paper and write down how much of your money you want to give to someone. This is called a "guodian chu slip."
The person you give the slip to can then take it to the bank and exchange it for the actual amount of money you wrote down.
Basically, guodian chu slips are a way to safely give people a small amount of your money without giving away your entire account balance.