Dog + dog = sheep, dog + horse = 10 sheep, among which dog = 10 kg, how much does the horse weigh?
狗+狗=羊，狗+马=10只羊，其中狗=10千克，马重多少千克？
<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<gadget id="calculator">10 * 20</gadget>
<output>200</output>

<gadget id="calculator">200 - 10</gadget>
<output>190</output>

<result>190</result>