Xiaoqian went on an outing with grandpa, grandma, father, and mother. The average cost per person is 138 yuan, how much is the total cost?
小倩和爷爷、奶奶、爸爸、妈妈一起去郊游．平均每位花费138元，一共花费多少元？
<gadget id="calculator">138 * 5</gadget>
<output>690</output>

<result>690</result>