Mom bought things with 4 pieces of 5 yuan, and got back 6 yuan, how much did my mother spend?
妈妈用4张5元钱买东西，找回6元，妈妈花了多少元钱．
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<gadget id="calculator">20 - 6</gadget>
<output>14</output>

<result>14</result>