It costs 18 yuan to buy (9/2) kilograms of apples. How much is an average apple per kilogram?
买(9/2)千克的苹果用去18元钱．平均每千克苹果多少元？
<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">18 / (9/2)</gadget>
<output>4</output>

<result>4</result>