Why all the undefined different

How can something be undefined if there are two different undefined and they do something different?
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Infinity and 0/0 are basically the same. Division in a sense is repeated subtraction. Here’s an example: a/b. You would keep subtracting b from a until a reached 0. However, in the case of a/0, you would keep subtracting 0 from a, but a would never reach 0 because you a subtracting nothing. But if a = 0 you have nothing to subtract from, making it even more weird, hence being ‘infinity’ because of ‘infinitely subtracting zeros’