The original price of a schoolbag is 120 yuan, how much is the price after a 10% discount?
一个书包的原价是120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">120 * (9/10)</gadget>
<output>108</output>

<result>108</result>