The original price of a schoolbag is 50 yuan, how much is the price after the 10% discount?
一个书包原价是50元，打九折后的价钱是多少元？
<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">50 * (9/10)</gadget>
<output>45</output>

<result>45</result>