Among the ginkgo trees planted in the school, except for one that died unexpectedly, the other four are flourishing. What is the survival rate of these ginkgo trees in the school?
学校栽的银杏树除1棵意外死亡外，其余4棵枝繁叶茂，学校这批银杏树的成活率是多少．
<gadget id="calculator">4 + 1</gadget>
<output>5</output>

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

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

<gadget id="calculator">(4/5) * 1</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>