On Sunday, Xiaoxiao asked his father for some money to buy books in the bookstore. Xiaoxiao spent 80 yuan, which was just the money given by his father (4/5). How much money did Xiaoxiao’s father give Xiaoxiao? buy books.
星期日，笑笑向他的爸爸要了一些钱去书城买书，笑笑用去80元，只是用去他爸爸给的钱的(4/5)，笑笑爸爸给了多少元钱让笑笑去买书．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">80 / (4/5)</gadget>
<output>100</output>

<result>100</result>