If a 2-digit number is written with 2 in front of it, the resulting 3-digit number is 9 times the original 2-digit number. What is the original 2-digit number?
一个两位数，在它的前面写上2，所得的三位数是原来两位数的9倍，原来的两位数是多少？
<gadget id="calculator">9 - 1</gadget>
<output>8</output>

<gadget id="calculator">200 / 8</gadget>
<output>25</output>

<result>25</result>