A set of famous books is priced at 120 yuan in a bookstore, and Xiao Ming only spent 105 yuan to buy this set of books from the Internet. How much cheaper is it for Xiao Ming to buy this set of books.
一套名著在书店售价120元，小明从网上购买这套书只用了105元，小明购买这套书便宜了多少．
<gadget id="calculator">120 - 105</gadget>
<output>15</output>

<gadget id="calculator">15 / 120</gadget>
<output>1/8 = around 0.125</output>

<result>1/8 = around 0.125</result>