There are 12 balls, take out all (1/4), how many should be taken.
有12个球，拿出全部的(1/4)，应该拿多少个．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">12 * (1/4)</gadget>
<output>3</output>

<result>3</result>