There is a four-digit number. After adding a decimal point to it, add it to the original number. The sum is 3016.87. What is the original four-digit number?
有个四位数，给它加上小数点后，再与原来的数相加，和是3016.87，原来的四位数是多少．
<gadget id="calculator">100 + 1</gadget>
<output>101</output>

<gadget id="calculator">3_016.87 / 101</gadget>
<output>29.87</output>

<gadget id="calculator">29.87 * 100</gadget>
<output>2_987</output>

<result>2_987</result>