Xiao Ming's money can just buy 5 pens with a unit price of 12 yuan. If you buy fountain pens, you can buy 20. How much is each fountain pen?
小明的钱正好可以买5支单价为12元的钢笔．如果买水笔，可以买20支，水笔每支多少元？
<gadget id="calculator">5 / 20</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">12 * (1/4)</gadget>
<output>3</output>

<result>3</result>