Why does 9 × 10 = 90?

Because adding 9 10's together makes 90.

That is, because 10 + 10 + 10 + 10 + 10 + 10 + 10 + 10 + 10 = 90.

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Keep practicing
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Why does 9 × 10 = 90?

Because adding 9 10's together makes 90.

That is, because 10 + 10 + 10 + 10 + 10 + 10 + 10 + 10 + 10 = 90.

Keep practicing