ELI5: if you have an infinite math string that goes 1 - 1 + 1 - 1 + 1 - 1... forever, why do mathematicians say the answer is 0.5? if you stop at any real point the answer is always either 1 or 0, so where the hell does a half come from?

ELI5: if you have an infinite math string that goes 1 - 1 + 1 - 1 + 1 - 1... forever, why do mathematicians say the answer is 0.5? if you stop at any real point the answer is always either 1 or 0, so where the hell does a half come from?