A total of 180 trees planted by sixth graders survived, and 20 trees did not survive. What is the survival rate of these trees?
六年级同学植树共存活180棵，未存活20棵，求这批树的存活率？
<gadget id="calculator">180 + 20</gadget>
<output>200</output>

<gadget id="calculator">180 / 200</gadget>
<output>9/10 = around 0.9</output>

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

<gadget id="calculator">(9/10) * 1</gadget>
<output>9/10 = around 0.9</output>

<result>9/10 = around 0.9</result>