Last week, Papa Hua bought a copy of "The Blue Dolphin Island" for Qiuyue with 20 yuan. Qiuyue has read 120 pages, which is less than the remaining unread pages (1/4). How many pages is this book?
上周爸爸华20元钱为秋月买了一本《蓝色的海豚岛》．秋月已经读了120页，比剩下未读的页数少(1/4)．这本书共多少页？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">120 / (3/4)</gadget>
<output>160</output>

<gadget id="calculator">160 + 120</gadget>
<output>280</output>

<result>280</result>