The sum of 2 times a number plus 1.8 is 16. Find this number.
一个数的2倍加上1.8的和是16，求这个数．
<gadget id="calculator">16 - 1.8</gadget>
<output>14.2</output>

<gadget id="calculator">14.2 / 2</gadget>
<output>7.1</output>

<result>7.1</result>