Pork prices dropped by 20% in June compared to May, and rose by 30% in August compared to June. Has the price in August increased or decreased compared to May, and how much has it changed?
猪肉价格6月份比5月份降了20%，8月份比6月份涨了30%，8月的价格和5月比是涨了还是降了，变化幅度多少？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 + (3/10)</gadget>
<output>13/10 = around 1.3</output>

<gadget id="calculator">(4/5) * (13/10)</gadget>
<output>26/25 = around 1.04</output>

<gadget id="calculator">(26/25) - 1</gadget>
<output>1/25 = around 0.04</output>

<result>1/25 = around 0.04</result>