There are 21 basketballs in the school sports room, and the number of volleyballs is 2/3 of that of basketballs. How many volleyballs are there?
学校体育室有篮球21个，排球个数是篮球的(2/3)，排球有多少个？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">21 * (2/3)</gadget>
<output>14</output>

<result>14</result>