Maple Leaf Garment Factory produces a batch of shirts, and distributes the tasks to the first and second branch factories on a 5:3 basis. The second branch factory actually produced 1080 pieces, exceeding 20% of the assigned task. How many shirts does the first branch factory produce?
枫叶服装厂生产一批衬衫，把任务按5：3分给一、二两个分厂，二分厂实际生产了1080件，超过分配任务的20%，一分厂生产衬衫多少件？
<gadget id="calculator">5 + 3</gadget>
<output>8</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<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">(3/8) * (6/5)</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">1_080 / (9/20)</gadget>
<output>2_400</output>

<gadget id="calculator">2_400 - 1_080</gadget>
<output>1_320</output>

<result>1_320</result>