Ok, so you know how sometimes grown-ups have to check if everything is going well in a company or organization? They do this to make sure that things are fair and all the rules are being followed. This is called an audit.
Now, sometimes instead of just looking at papers and documents, grown-ups use special tools on a computer to help them check everything really carefully. These tools are called Computer Assisted Audit Tools or CAATs for short.
So, imagine you have a lot of papers with numbers on them and you want to double-check if they are all correct. Instead of counting by hand, a CAAT can help you do this quickly and accurately. It can also help you find mistakes or even fraud if someone has done something wrong on purpose.
It's like having a special grown-up helper who can use technology to do the work better and faster. This way, they can make sure everything is done correctly and everybody is following the rules.