Xiao Ming has pocket money of 28 yuan, and he took out (2/7) of it to buy a pencil case. How much did Xiao Ming spend on the pencil case?
小明有零花钱28元，他拿出其中的(2/7)买了一个文具盒，小明花了多少钱买文具盒？
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">28 * (2/7)</gadget>
<output>8</output>

<result>8</result>