(4/5) of a bottle of pesticide is exactly (2/5) L, how many L of pesticide is there in this bottle?
一瓶农药的(4/5)正好是(2/5)L，这瓶农药有多少L．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

<gadget id="calculator">(2/5) / (4/5)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>