Sixth grade students planted 200 trees on Arbor Day, but 50 failed to survive. Find the survival rate.
六年级学生在植树节种活了200棵树，50棵没成活，求成活率．
<gadget id="calculator">200 + 50</gadget>
<output>250</output>

<gadget id="calculator">200 / 250</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>