A professional farmer raised 4,000 ducks this year. After one month, the survival rate was 80%, and 200 ducks died later. What is the final survival rate of this batch of ducks?
养殖专业户今年养了4000只鸭，一个月后成活率是80%，后来又死了200只．这批鸭最后的成活率是百分之几？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">4_000 * (4/5)</gadget>
<output>3_200</output>

<gadget id="calculator">3_200 - 200</gadget>
<output>3_000</output>

<gadget id="calculator">3_000 / 4_000</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">100 / 100</gadget>
<output>1</output>

<gadget id="calculator">(3/4) * 1</gadget>
<output>3/4 = around 0.75</output>

<result>3/4 = around 0.75</result>