A batch of goods, transported away (9/10), is exactly (7/2) tons, how many tons of this batch of goods are left unshipped?
一批货物，运走(9/10)，正好是(7/2)吨，这批货物还剩多少吨没有运？
<gadget id="calculator">7 / 2</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">9 / 10</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">(7/2) / (9/10)</gadget>
<output>35/9 = around 3.888889</output>

<gadget id="calculator">(35/9) - (7/2)</gadget>
<output>7/18 = around 0.388889</output>

<result>7/18 = around 0.388889</result>