2 times a number minus the product of 2.6 and 4, the difference is 10, what is this number?
一个数的2倍减去2.6与4的积，差是10，这个数是多少？
<gadget id="calculator">2.6 * 4</gadget>
<output>10.4</output>

<gadget id="calculator">10 + 10.4</gadget>
<output>20.4</output>

<gadget id="calculator">20.4 / 2</gadget>
<output>10.2</output>

<result>10.2</result>