我国一些化工厂把大面积沙漠变成“排污宝地”，将未经处理的污水排入沙漠。结合漫画（如图），完成下列问题。

阅读理解
    Hi. I am Maya. I am 13 years old. I am from Africa. My father is a teacher and my mother works in a hospital. Now they are working in Beijing. They both like their work and work very hard. My father's favorite animal is the panda, but I like dolphins best.
    I am studying in a middle school. And I like music and drawing best. I want to be a designer. I like to design my room. I like the color pink, so there are a lot of pink things in my room.
    I have three friends in my room. They are Mike, Dora and Peter. They are my toys. I love them. Every night, they sleep with me.

如图，地面上有三个洞口A、B、C，老鼠可以从任意一个洞口跑出，猫为能同时最省力地顾及到三个洞口（到A、B、C三个点的距离相等），尽快抓到老鼠，应该蹲守在（   ）

化肥对提高农作物的产量具有重要的作用，碳铵（碳酸氢铵）就是农民朋友经常使用的一种氮肥，碳铵易溶于水、受潮时常温分解，温度越高分解越快，遇碱时放出氨气．某校化学兴趣小组为测定某碳铵肥料样品的纯度，将8.5g样品加入足量的浓氢氧化钠溶液中共热，（碳铵中的杂质不与氢氧化钠反应，反应的方程式为NH₄HCO₃+2NaOH=Na₂CO₃+2H₂O+NH₃↑），把产生的所有NH₃用足量的硫酸溶液吸收，同时测量两分钟内硫酸溶液增加的质量，结果如下表所示．

试回答下列问题：

一本书共365页，在编制页码时共用了____ 个数字．（如12用了两个数字）