Two adults take a few children to the park. Tickets for adults are 10 yuan per person, and tickets for children are 5 yuan per person. The total cost of buying tickets is 45 yuan. How many children do these two adults bring?
两个大人带几个小孩去公园游玩，大人门票每人10元，小孩门票每人5元，买门票一共花了45元，则这两个大人带了多少个小孩．
<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<gadget id="calculator">45 - 20</gadget>
<output>25</output>

<gadget id="calculator">25 / 5</gadget>
<output>5</output>

<result>5</result>