There were 200 girls in a certain school last year, and the difference between the number of boys and girls is 80. Because the number of girls this year is 20% higher than last year, and the number of boys is reduced, the number of girls is 30 more than boys.
某校去年女生是200人，男生和女生人数的差是80，因为今年比去年女生增加20%，男生减少多少，女生比男生多了30人．
<gadget id="calculator">200 + 80</gadget>
<output>280</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">200 * (6/5)</gadget>
<output>240</output>

<gadget id="calculator">240 - 30</gadget>
<output>210</output>

<gadget id="calculator">280 - 210</gadget>
<output>70</output>

<gadget id="calculator">70 / 280</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>