There is a two-digit number, add the number 1 in front of it to get a three-digit number, and add it to the back to get a three-digit number, the difference between these two three-digit numbers is 666. What is the original two-digit number.
有一个两位数，把数码1加在它的前面可以得到一个三位数，加在它的后面也可以得到一个三位数，这两个三位数相差666．原来的两位数是多少．
<gadget id="calculator">666 - 1</gadget>
<output>665</output>

<gadget id="calculator">100 + 665</gadget>
<output>765</output>

<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">765 / 9</gadget>
<output>85</output>

<result>85</result>