How many kilograms is 80% of (4/5) ton?
(4/5)吨的80%是多少千克．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(4/5) * (4/5) * 1_000</gadget>
<output>640</output>

<result>640</result>