A theorem is like a magic trick that smart people use to figure out things about math and science. Just like a magician has a trick that they know how to do really well, mathematicians and scientists have theorems that they use to figure out tricky problems.
Think of it like building with blocks. You have lots of little blocks that you can stack up to make a tower. You can only stack them in certain ways or the tower will fall down. It's the same with math and science problems. There are certain rules you have to follow to solve them correctly.
A theorem is like a special rule that tells you how to solve a certain type of problem. It's like a shortcut that can help you figure out the answer to a really hard question. Just like a magician can't do a trick without knowing the steps, mathematicians and scientists can't use a theorem to solve a problem without following the rules that go along with it.
So next time you're building with blocks or working on a tricky math problem, remember that just like a magician has a trick, mathematicians and scientists have theorems to help them solve problems. And with practice and hard work, maybe you can master some tricks of your own!