There are 100 books in Xiaoxiao’s family, 75% of which are story books, and the rest are science and technology books. After buying some science and technology books, science and technology books account for 40% of the total. How many books does Xiaoxiao’s family have now?
笑笑家共有图书100本，其中75%是故事书，其他是科技书，又买进一些科技书后，科技书占总数的40%，现在笑笑家共有多少本图书．
<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">100 * (3/4)</gadget>
<output>75</output>

<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">75 / (3/5)</gadget>
<output>125</output>

<result>125</result>