Mom bought 6 kilograms of apples and pears, and spent 22 yuan, 4 yuan per kilogram of apples, and 3 yuan per kilogram of pears. How many kilograms of apples did mother buy back?
妈妈买苹果和梨共6千克，花了22元，每千克苹果4元，每千克梨3元，妈妈买回苹果多少千克．
<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<gadget id="calculator">24 - 22</gadget>
<output>2</output>

<gadget id="calculator">4 - 3</gadget>
<output>1</output>

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

<gadget id="calculator">6 - 2</gadget>
<output>4</output>

<result>4</result>