if n=8^11-8, what is the units digit of n?
0 1 4 6 8 ans 6
no idea and can not find the explaination a
and 28 the sum of the first n positive integers equals n(n+1)/2, the sum of all the even integers between 99 and 301,
ans 20,200
Sn=a1n+n(n-1)d/2
d=2, so should be 301*300-99*98, no answerr a | 
