Question——问题 0:
What is the answer of the ultimate question of life, universe and everything?
关于生命，宇宙和一切的最终问题的答案是什么？
kelvinli's Answer: From an unknown book: 42. right

Question——问题 1:
a,b,c are positive integers.
Slove: a*a+b*b+c*c=a*a*b*b
a,b,c是正整数。
解方程：a*a+b*b+c*c=a*a*b*b

Question——问题 2:
Find the fault of the proof.
1 is the biggest interger.
Proff: If the biggest interger is not 1 but x, then we have x*x>x,
so it's contradictory to the saying "x is the biggest integer".
So 1 is the biggest integer.
指出以下证明中的错误：
1是最大的正整数。
证明：假设最大的正整数不是1而是x，那么x*x>x，
这个之前假设的“x是最大的正整数”矛盾。
所以1是最大的正整数。
S0nic whooshx's Answer: Since there is not a biggest positive integer, we cannot use this as a valid proof. (在证明1是最大的正整数之前必须先证明最大的正整数是存在的) right

Question——问题 3:
Xiao Ming buy potato chips, every potato chips has a sticke from xiyangyang.
A set of the sticker is n, the chance that every sticke appears is same.
How many mathematical expectation f(n) that how much potato chips xiaoming needs to buy in average is it?
小明买薯片，买薯片送喜羊羊贴纸，每包一张。
一套喜羊羊贴纸是n张，小明买中任何一张喜羊羊贴纸的概率是一样的。
小明集齐一套喜羊羊贴纸所需购买的薯片包数f(n)的数学期望是多少？

Question——问题 4:
Slove the nonlinear differential equations. (^ is the powers symbol)
y''(1-y)^2=1, y'(0)=y(0)=0
解非线性微分方程。（^是乘方号）
y''(1-y)^2=1, y'(0)=y(0)=0

Question——问题 5:
We know the coordinate position of two points O(Ox,Oy),P(Px,Py) on cartesian plane.
There is a point H(Hx,Hy) which meet (Hx-Ox)^2+(Hx-Oy)^2=r^2 and PH⊥OH.
Slove the linear equations of line PH.
已知平面上两点坐标为O(Ox,Oy),P(Px,Py)。
现有一点H(Hx,Hy)满足(Hx-Ox)^2+(Hx-Oy)^2=r^2并且PH⊥OH。
求直线PH的一般式方程。

Question——问题 6:
In spatial Cartesian coordinate system, r1,r2,n,s are vectors and n=r1×r2.
Proof: |n*s|/|n|=|s+(n×s*r1*r2-n×s*r2*r1)/n^2|
在空间直角坐标系中，r1,r2,n,s为向量，n=r1×r2。
求证：|n*s|/|n|=|s+(n×s*r1*r2-n×s*r2*r1)/n^2|

Question——问题 7:
(Question only for those who do not know chinese)
What's the name of Confucius?
agentdark1706's answer: Kong Qiu (孔丘). right

Question——问题 8:
How many kinds of curves of slider are there in game OSU!? Give the name of all the curves.
在OSU!游戏中的滑条共有多少种曲线？请说出所有曲线的名称。
Nitori's answer: There are 2 kinds of sliders in osu. Catmull and Bezier. wrong

Question——问题 9:
In game OSU!, what frequency is it when auto mods hit a spinner in a Taiko mode?
在OSU!游戏中，auto模式击打太鼓转盘的频率是多少？

Question——问题 10:
Let <A,∨,∧,ˉ> be the Finite Boolean algebra of Finite Boolean lattice <A,≤>.
S is the set which combines all atoms in <A,≤>. ξ(S) is the Power set of S.
Proof: <A,∨,∧,ˉ> and <ξ(S),∪,∩,~>are isomorphic.
设<A,∨,∧,ˉ>是由有限布尔格<A,≤>诱导的一个有限布尔代数。
S是布尔格<A,≤>中所有原子的集合。ξ(S)是S的幂集。
求证：<A,∨,∧,ˉ>和<ξ(S),∪,∩,~>同构。

Question——问题 11:
What is the Compression algorithms of the .osz file?
.osz文件的压缩算法是什么？

Question——问题 12:
In .ose file, What is the biggest difference between format v3 and v4?
在.osu文件中，v3版本和v4版本最大的差别是什么？