Columnar calculation: the original price of a schoolbag is 105 yuan, how much is the 40% discount?
列式计算：一个书包原价105元，四折出售是多少元？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">105 * (2/5)</gadget>
<output>42</output>

<result>42</result>