2 plus (2/5) of a number, the sum is 18, what is this number?
2加上一个数的(2/5)，和是18，这个数是多少？
<gadget id="calculator">18 - 2</gadget>
<output>16</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">16 / (2/5)</gadget>
<output>40</output>

<result>40</result>