Three days before the National Day, my mother gave some money to Benbenxiong. On the first day, Benbenxiong went to Xinhua Bookstore to buy books and spent (1/4) of the money; on the second day, he also went to the toy store and spent the rest of the money (1/3); on the third day, Benbenxiong decided to use the last 20 yuan to buy a gift for his parents, so how much money did his mother give to Benbenxiong?
国庆前三天，妈妈给了笨笨熊一些钱，第一天笨笨熊去新华书店买书，花掉了(1/4)的钱；第二天也去了玩具店，花掉了剩余钱的(1/3)；第三天笨笨熊决定用最后的20元钱给爸爸妈妈买份礼物，那么妈妈给了笨笨熊多少元钱．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

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

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">20 / (2/3) / (3/4)</gadget>
<output>40</output>

<result>40</result>