The average price of pork last month was 12 yuan per kilogram, but this month it has risen to 15 yuan. How much has the price increased?
猪肉上月平均每千克是12元，本月涨到了15元，价格涨了多少．
<gadget id="calculator">15 - 12</gadget>
<output>3</output>

<gadget id="calculator">3 / 12</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>