It is known that 9*9=81, 99*99=9801, 999*999=998001, so how much is 9999999*9999999=.
已知9*9=81，99*99=9801，999*999=998001，那么9999999*9999999=多少．
<gadget id="calculator">9_999_999 * 9_999_999</gadget>
<output>99_999_980_000_001</output>

<result>99_999_980_000_001</result>