The turnover of a store in August increased by 50% compared with July, and the turnover in September decreased by 20% compared with August. How much more turnover in September than in July.
某商店8月份的营业额比7月份增多50%，9月份营业额比8月份又降低20%．9月份的营业额比7月份增多多少．
<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 + (1/2)</gadget>
<output>3/2 = around 1.5</output>

<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">(3/2) * (4/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">(6/5) - 1</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>