The school held a table tennis competition. There were 64 participants in the fourth grade, 16 less than the fifth grade. The total number of participants in the fourth and fifth grades was 9 times more than that of the third grade. How many people participated in the third grade?
学校举行乒乓比赛，四年级有64人参加，比五年级少参加16人，四、五年级参加的总人数比三年级的3倍多9人，三年级有多少人参加？
<gadget id="calculator">64 + 16</gadget>
<output>80</output>

<gadget id="calculator">64 + 80</gadget>
<output>144</output>

<gadget id="calculator">144 - 9</gadget>
<output>135</output>

<gadget id="calculator">135 / 3</gadget>
<output>45</output>

<result>45</result>