A pile of goods, transported away (4/7), is exactly (12/5) tons, how many tons is this pile of goods?
一堆货物，运走(4/7)，正好是(12/5)吨，这堆货物有多少吨？
<gadget id="calculator">12 / 5</gadget>
<output>12/5 = around 2.4</output>

<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">(12/5) / (4/7)</gadget>
<output>21/5 = around 4.2</output>

<result>21/5 = around 4.2</result>