>Numbers don't "make" other numbers It's a standard English expression https://english.stackexchange.com/questions/9053/should-i-use-the-singular-or-plural-verb-in-mathematical-formulae-two-and-two >Those numbers "are" square roots of -1 Yes, square roots. Roots. Multiple roots. >But it is still one God just like i, j,k are one number No, they're three numbers, each of which when squared equals the number negative one. It isn't the case that i, j, and k, are each *the* square root of negative one. They are each *a* square root of negative one. The expression sqrt(-1) by itself doesn't clearly point to one number in the context of the quaternions. Strictly, sqare roots wouldn't point to just one number even in the integers, since, e.g. both 2 and -2 when squared equal four, except for the convention that sqrt(x) refers to only the positive root of x. But in the quaternions, there are multiple "positive roots" so the convention breaks down.

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