The sum of 6 and 2 times a number is 10.2, what is this number?
6与一个数的2倍的和是10.2，这个数是几？
<gadget id="calculator">10.2 - 6</gadget>
<output>4.2</output>

<gadget id="calculator">4.2 / 2</gadget>
<output>2.1</output>

<result>2.1</result>