gwd 10-27

XIAOYUE78

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

XIAOYUE78

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

stevegt

8的次方数，尾数是一循环，依序为8、4、2、6、
所以8^11的尾数应该是2，
然后减去8，所以答案应该是4…
这种题目很常见，要把握注其关键….