There are 180 students on the playground exercising, of which girls accounted for the total number (2/9), and then a few girls came, at this time the number of girls accounted for the total number (1/3), and then a few more came girl?
操场上有180名同学在锻炼身体，其中女生占总人数的(2/9)，后来又来了几名女生，这时女生人数占总人数的(1/3)，后来又来了几名女生？
<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">1 - (2/9)</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(7/9) / (2/3)</gadget>
<output>7/6 = around 1.166667</output>

<gadget id="calculator">180 * (7/6)</gadget>
<output>210</output>

<gadget id="calculator">210 - 180</gadget>
<output>30</output>

<result>30</result>