The school donated books for poor children. Class 41 donated 47 books, Class 42 donated 12 books less than Class 1, Class 3 donated twice the total of Class 1 and Class 2, Class 4 donated 4 Class 3 is twice as small as 20 books. How many books are donated by the four classes?
学校为贫困儿童捐书，四1班捐了47本，四2班比四1班少捐12本，四3班捐的是四1、四2总数的2倍，四4班捐的是四3班的2倍少20本．四个班一共捐多少本．
<gadget id="calculator">47 - 12</gadget>
<output>35</output>

<gadget id="calculator">47 + 35</gadget>
<output>82</output>

<gadget id="calculator">82 * 2</gadget>
<output>164</output>

<gadget id="calculator">164 * 2</gadget>
<output>328</output>

<gadget id="calculator">328 - 20</gadget>
<output>308</output>

<gadget id="calculator">47 + 35 + 164 + 308</gadget>
<output>554</output>

<result>554</result>