Xiaohong reads a book. After reading it for a few days, there are 210 pages left in the book. She then read 20% of the total. At this time, the ratio of the number of pages she has read to the number of pages she has not read is 3:2. How many pages does Xiaohong have not read?
小红看一本书，看了几天后，这本书还剩210页没有看．她接着又看了总数的20%，这时已看的页数与未看的页数比是3：2．小红还有多少页没有看？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(1/5) + (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">210 / (3/5)</gadget>
<output>350</output>

<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">350 * (2/5)</gadget>
<output>140</output>

<result>140</result>