7 numbers are arranged in a row. Their average is 25. The average of the first 4 numbers is 32. The average of the last 4 numbers is 20. What is the fourth number?
7个数排成一列，它们的平均数是25，前4个数得的平均数是32，后4个数的平均数是20，第四个数是多少？
<gadget id="calculator">32 * 4</gadget>
<output>128</output>

<gadget id="calculator">20 * 4</gadget>
<output>80</output>

<gadget id="calculator">128 + 80</gadget>
<output>208</output>

<gadget id="calculator">25 * 7</gadget>
<output>175</output>

<gadget id="calculator">208 - 175</gadget>
<output>33</output>

<result>33</result>