There are 180 girls in grade six, 10% less than boys. How many people are there in the sixth grade?
六年级有女生180人，比男生少10%．六年级一共有多少人？
<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">180 / (9/10)</gadget>
<output>200</output>

<gadget id="calculator">200 + 180</gadget>
<output>380</output>

<result>380</result>