Okay, so imagine you have a very big grid with a bunch of numbers in it. Let's call it a "matrix". Each row and column of the matrix has some numbers in it.
Now, let's say we want to do something called "computing the permanent". That means we want to find a special number that tells us something important about the matrix. This special number is called the "permanent" of the matrix.
But how do we find the permanent? Well, it's actually very complicated. There's no easy way to do it for big matrices.
One method is called the "brute force" method. This means we start by finding every possible way to choose one number from each row and column of the matrix. Then, we multiply all of those chosen numbers together and add them up. This gives us the permanent.
But the problem is, there are a LOT of ways to choose numbers from the matrix. So this method can take a very long time, especially for big matrices.
Another method is called the "Ryser algorithm". This is a bit more complicated, but the idea is to use some special math tricks to simplify the matrix and make it easier to find the permanent.
There are also some special cases where we can find the permanent more easily, like if the matrix is "bipartite". But these cases are rare and don't apply to most matrices.
Overall, computing the permanent is a very hard problem in math and computer science. It's something that researchers are still trying to figure out how to do efficiently for big matrices.