There are (4/5) tons of food in the store, and (1/5) tons are transported to support the disaster area, and (2/5) tons are sold. How many tons are left?
商店有食品(4/5)吨，支援灾区运走(1/5)吨，又卖出(2/5)吨，还剩多少吨？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(4/5) - (1/5) - (2/5)</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>