Uncle Zhang earns 109.2 yuan in the morning from selling apples, and 91 yuan in the afternoon. It is known that each kilogram of apples is 2.6 yuan, how many kilograms of apples are sold more in the morning than in the afternoon?
张大爷卖苹果上午的收入是109.2元，下午的收入是91元．已知每千克苹果2.6元，上午比下午多卖出多少千克苹果？
<gadget id="calculator">109.2 - 91</gadget>
<output>18.2</output>

<gadget id="calculator">18.2 / 2.6</gadget>
<output>7</output>

<result>7</result>