There is an eight-digit number, subtract 1 to become a seven-digit number, what is the eight-digit number?
有一个八位数，减去1就变成七位数，这个八位数是多少．
<gadget id="calculator">9_999_999 + 1</gadget>
<output>10_000_000</output>

<result>10_000_000</result>