Eat (3/5) of a box of biscuits, and there are (2/5) kilograms left, how many kilograms are there in this box of biscuits, and what is the correct formula
一盒饼干吃掉(3/5)，还剩(2/5)千克，这盒饼干原来有多少千克，正确列式是多少
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

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

<result>1</result>