For a four-digit number, add a decimal point in front of one of its digits, and then add it to the four-digit number. The result is 2920.92. What is the four-digit number?
一个四位数，在它的某位数字的前面加一个小数点，再和这个四位数相加，得数是2920.92，这个四位数是多少？
<gadget id="calculator">1 / 100</gadget>
<output>1/100 = around 0.01</output>

<gadget id="calculator">1 + (1/100)</gadget>
<output>101/100 = around 1.01</output>

<gadget id="calculator">2_920.92 / (101/100)</gadget>
<output>2_892</output>

<result>2_892</result>