There are 198 books on shelf A, and 160 books on shelf B. How many books are taken out from shelf A and placed on shelf B, and the number of books on shelf A and shelf B is equal?
甲书架有198本书，乙书架有160本书，从甲书架取出多少本书放入乙书架后，甲乙书架上的书的本数相等？
<gadget id="calculator">198 + 160</gadget>
<output>358</output>

<gadget id="calculator">358 / 2</gadget>
<output>179</output>

<gadget id="calculator">198 - 179</gadget>
<output>19</output>

<result>19</result>