Students A, B, and C count a pile of exercise books ranging from 80 to 100. A said: "I counted in two books and two places, and I just finished counting." B said: "I counted in three books and three places, just right. Finished counting." C said: "I counted five books and five places, and I just finished counting." Question: How many books are there in this pile of exercise books?
甲、乙、丙三位同学数一堆数量在80到100之间的练习本，甲说："我两本两本地数，正好数完．"乙说："我三本三本地数，正好数完．"丙说："我五本五本地数，也正好数完．"问：这堆练习本一共有多少本？
<gadget id="calculator">2 * 3 * 5</gadget>
<output>30</output>

<gadget id="calculator">30 * 3</gadget>
<output>90</output>

<result>90</result>