After pouring out (1/2) of a glass of water, there is still (1/2) kilograms left. How many kilograms does this glass of water have? What is the correct column
一杯水，倒出(1/2)后，还剩(1/2)千克，这杯水原有多少千克？正确的列式是多少
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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

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

<result>1</result>