The school shipped 200 saplings, the teacher planted 10%, and the rest were allocated to the fourth, fifth, and sixth classes according to the ratio of 2:3:4. How many saplings were allocated to the sixth grade?
学校运来200棵树苗，老师栽种了10%，余下的按2：3：4分配给四、五、六三个班级，六年级分到多少棵？
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

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

<gadget id="calculator">200 * (9/10)</gadget>
<output>180</output>

<gadget id="calculator">2 + 3 + 4</gadget>
<output>9</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">180 * (4/9)</gadget>
<output>80</output>

<result>80</result>