Students from three classes in grade six planted trees together. Among them, the first class planted 80 trees, the second class planted more trees than the first class (9/8), the third class planted more trees than the second class (7/9), how many trees were planted by the third class?
六年级三个班学生共同植树．其中，一班植树80棵，二班植树的棵数是一班的(9/8)，三班植树的棵数比二班多(7/9)，三班植树多少棵？
<gadget id="calculator">9 / 8</gadget>
<output>9/8 = around 1.125</output>

<gadget id="calculator">7 / 9</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">1 + (7/9)</gadget>
<output>16/9 = around 1.777778</output>

<gadget id="calculator">80 * (9/8) * (16/9)</gadget>
<output>160</output>

<result>160</result>