It's not such a complicated problem, nor a joke, but the difficulty lies in figuring out what it is all about just on the basis of the numbers given below. So, if you have some TIME left, think about it and have fun!
And then discuss it with your kids. It is a concept that they will be able to understand more or less well, depending on their age and degree of development. But this subject - just like for you - will concern them for life!
What is it all about?
2 = 120
3 = 72
4 = 28
5 = 60
Picture: Little IQ test (ChildUp.com)