book is reduced from 48 yuan to 30 yuan, how much is the price cut?
一本书由原来48元降低到30元，降价百分之几？
<gadget id="calculator">48 - 30</gadget>
<output>18</output>

<gadget id="calculator">18 / 48</gadget>
<output>3/8 = around 0.375</output>

<result>3/8 = around 0.375</result>