Xiaojun went on a trip with his father and mother, and spent a total of 900 yuan on the bus ticket. The adult ticket was 380 yuan, and how much was the child ticket?
小军和爸爸、妈妈一起外出旅游，买车票共花了900元，成人票是一张380元，儿童票一张是多少元？
<gadget id="calculator">380 * 2</gadget>
<output>760</output>

<gadget id="calculator">900 - 760</gadget>
<output>140</output>

<result>140</result>