Plant a batch of saplings, the ratio of the number of surviving trees to the number of dead trees is 4:1, what is the survival rate of this batch of saplings?
种一批树苗，成活棵数与死去的棵数的比是4：1，这批树苗的成活率是多少．
<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>