For a bag of rice, the ratio of what is used to what is left is 4:5, and there are 25 kilograms left, how many kilograms are used?
一袋大米，用去的与剩下的比是4：5，剩下25千克，用去多少千克？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">25 * (4/5)</gadget>
<output>20</output>

<result>20</result>