There are 50 students in class 51 who participated in the final math test, and 45 of them got excellent grades. What is the excellent rate of math grades in class 51?
五1班参加期末数学测试的有50人，其中45人的成绩是优秀，五1班数学成绩的优秀率是多少．
<gadget id="calculator">45 / 50</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>