Xiaoxiao goes to Sea World with her father, mother, grandpa, and grandma. How much is the round-trip transportation fee? (Note: One-way fare is 12.5 yuan per person, half price for children)
笑笑和爸爸、妈妈、爷爷、奶奶去海洋世界，往返交通费要用多少钱？(注：单程票价每人12.5元，儿童半价)
<gadget id="calculator">12.5 * 4</gadget>
<output>50</output>

<gadget id="calculator">12.5 / 2</gadget>
<output>6.25</output>

<gadget id="calculator">50 + 6.25</gadget>
<output>56.25</output>

<gadget id="calculator">56.25 * 2</gadget>
<output>112.5</output>

<result>112.5</result>