Zhang Xin reads a 240-page book. The ratio of the number of pages he has read to the number of pages he has not read is 2:3. How many pages are left?
张辛看一本240页的书，已看的页数和未看的页数的比是2：3，还剩多少页没看？
<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">240 * (3/5)</gadget>
<output>144</output>

<result>144</result>