The school buys back 5 boxes of balls. If 20 balls are taken out from each box, there will be 20 more balls left in each box than the original one. How many balls are in each box?
学校买回5箱皮球，如果从每箱中取出20个皮球，每箱剩下的比原来的一半多20个，原来每箱多少个皮球？
<gadget id="calculator">20 + 20</gadget>
<output>40</output>

<gadget id="calculator">40 * 2</gadget>
<output>80</output>

<result>80</result>