Four children buy a 60 yuan boat together. The first child pays half of the total amount paid by the other children, the second child pays one-third of the total amount paid by the other children, and the third child pays the amount paid by the other children A quarter of the total amount, how much did the fourth child pay?
四个孩子合买一只60元的小船．第一个孩子付的钱是其他孩子付的总钱数的一半，第二个孩子付的钱是其他孩子的总钱数的三分之一，第三个孩子付的钱是其他孩子付的总钱数的四分之一，第四个孩子付了多少钱？
<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 + 4</gadget>
<output>5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/3) - (1/4) - (1/5)</gadget>
<output>13/60 = around 0.216667</output>

<gadget id="calculator">60 * (13/60)</gadget>
<output>13</output>

<result>13</result>