Xingxing Garment Factory received an order and planned to process 100 sets per day, and finished it in a few days. When the order was completed (4/5), it received a notice of delivery in advance, so it speeded up, and now it processes 20% more than before. The result was completed 1 ahead of schedule. How many sets are there in this order?
星星服装厂接到一个订单，计划每天加工100套，若干天完成，当完成订单的(4/5)时，接到提前交货的通知，于是加快速度，现在每天比原来多加工20%，结果提前1完成．这批订单共多少套？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">100 * (6/5)</gadget>
<output>120</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">100 * (4/5)</gadget>
<output>80</output>

<gadget id="calculator">100 * (6/5) * (4/5)</gadget>
<output>96</output>

<gadget id="calculator">120 - 100 - 96</gadget>
<output>-76</output>

<gadget id="calculator">80 + (-76)</gadget>
<output>4</output>

<gadget id="calculator">120 / 4</gadget>
<output>30</output>

<gadget id="calculator">100 * 30</gadget>
<output>3_000</output>

<result>3_000</result>