1^3尾数1
2^n尾数为2,4,8,6,2,4,8,6,所以2^4尾数为6
3^n尾数为3,9,7,1,3,9,7,1,所以3^5尾数为3
4^n尾数为4,6,4,6,4,6,4,6,所以4^6尾数为6
5^n尾数一定是5
6^n尾数一定是6
7^n尾数为7,9,3,1,7,9,3,1,所以7^9尾数为7
8^n尾数为8,4,2,6,8,4,2,6,所以8^10尾数为4
9^n尾数为9,1,9,1...所以9^11尾数为9
1+6+3+6+5+6+7+4+9=47
所以原式尾数为7.