Mom bought 6 kilograms of cucumbers and tomatoes, and spent 10 yuan. It is known that cucumbers are 1.4 yuan per kilogram and tomatoes are 2.2 yuan per kilogram. How many kilograms of cucumbers did my mother buy?
妈妈买黄瓜和西红柿共6千克，花了10元．已知黄瓜每千克1.4元，西红柿每千克2.2元，妈妈买了多少千克黄瓜．
<gadget id="calculator">6 * 2.2</gadget>
<output>13.2</output>

<gadget id="calculator">13.2 - 10</gadget>
<output>3.2</output>

<gadget id="calculator">2.2 - 1.4</gadget>
<output>0.8</output>

<gadget id="calculator">3.2 / 0.8</gadget>
<output>4</output>

<result>4</result>