A total of 8 balls are placed in the box. If the probability of touching a red ball is (1/4), how many red balls should be placed in the box.
盒子里共放8个球，如果摸到红球的可能性是(1/4)，盒子里应放多少个红球．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">8 * (1/4)</gadget>
<output>2</output>

<result>2</result>