Students from class 6 and 4 participated in the tree planting activity. As a result, 18 trees survived and 2 died. What is the survival rate of the tree planted in this class?
六4班同学参加植树活动，结果活了18棵，死了2棵，该班植树的成活率是多少．
<gadget id="calculator">18 + 2</gadget>
<output>20</output>

<gadget id="calculator">18 / 20</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>