The electricity consumption of the experimental primary school in October is 1200 kWh, which is 20% less than that in September. How much is the electricity consumption of the school in September? (Write a relational expression and answer it in two ways)
实验小学十月份的用电量是1200度，比九月份节省20%，学校九月份的用电量是多少度？(写关系式，用两种方法解答)
<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">1_200 / (4/5)</gadget>
<output>1_500</output>

<result>1_500</result>