Xiaoming fills the bucket with water. If half of the water is used up, the iron bucket and water will weigh 6 kilograms; if the water is removed (2/5), the total weight of the iron bucket and water will be 7 kilograms. So how much does the barrel weigh?
小明用桶装满了水，如果用去一半水后，铁桶和水共重6千克；如果用去水的(2/5)，铁桶和水共重7千克．那么桶重多少千克．
<gadget id="calculator">7 - 6</gadget>
<output>1</output>

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

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

<gadget id="calculator">(1/2) - (2/5)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 / (1/10)</gadget>
<output>10</output>

<gadget id="calculator">10 * (1/2)</gadget>
<output>5</output>

<gadget id="calculator">6 - 5</gadget>
<output>1</output>

<result>1</result>