20% of 200 kilograms of rice is used up, how many kilograms are left?
200千克大米用去了20%，还剩下多少千克？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">200 * (4/5)</gadget>
<output>160</output>

<result>160</result>