Jiajia's extracurricular books belong to Xiaojie (4/5). If Xiaojie gives Jiajia 5 books, they both have the same number of extracurricular books. How many extracurricular books does Jiajia have?
佳佳课外书的本数是小洁的(4/5)，如果小洁给佳佳5本，那么两人的课外书就同样多，佳佳原有多少本课外书？
<gadget id="calculator">5 + 5</gadget>
<output>10</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">10 / (1/5)</gadget>
<output>50</output>

<gadget id="calculator">50 * (4/5)</gadget>
<output>40</output>

<result>40</result>