数学:遇到几个JJ题.
1.韩国JJ里面的那个算周长的题目,有很多六边形在一起的
2.A 6 bicyclists has to be chosen from 4 adult and 4 children
Col A: 选2个大人和4个小孩
Col B: 选各3个
3.S = {1, 2, 3, 4, 5 } T = {6, 7, 8, 9, 10}. 加起来不重复的答案.是9.
4.求standard deviation的,好象是-a,-b,-c,0,a,b,c 和 -a^,-b^,-c^,0,a^,b^,c^两组.