The price of a commodity in May is 30% lower than that in April, and the price in June is 30% higher than that in May. Has the price in June increased or decreased compared with the price in April? What is the magnitude of the change.
一种商品5月份的价格比4月份的价格降了30%，六月份的价格比5月份的价格又涨了30%．六月份的价格与4月份的价格比较是涨了还是降了呢？变化幅度是多少．
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (3/10)</gadget>
<output>7/10 = around 0.7</output>

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

<gadget id="calculator">(7/10) * (13/10)</gadget>
<output>91/100 = around 0.91</output>

<gadget id="calculator">1 - (91/100)</gadget>
<output>9/100 = around 0.09</output>

<result>9/100 = around 0.09</result>