In Primary you learn that infinite is a expression that is infinitely long. What if we want to count how much integers there are and real numbers such as: So, lets say we have a computer that downloads all the integers and real numbers but we can add a new real number by doing: So basically the we add 1 to the units of the first number then the second and so on. If it is 9 set it as 0 this works because it is different to the 1,2,3,4,5,6...(this means the first number saved) so on. This proves the relevance of different values off infinite. I think veritasium explains this the best.