Question

求5+55+555……的前十项的和

运行结果都是错误的啊??

你们的答案都自己运行过吗???

Answer 1

经计算得出结果是

5/9[（10^11-10）/9-10]

如图所示

Answer 2

String s="5";
int a=0;
for(int i=0;i<10;i++){
a=a+Integer.parseInt(s);
s=s+"5";
}
System.out.println(a);

Answer 3

int sum=0;
int n=10;
for(int i=0;i<=n;i++){
sum=sum+((10^n-1)/9)*5;
}
System.out.println(sum);

Answer 4

for (int i = 0; i <10; i++){
a = a*10+5;
sum = sum + a;
}

Answer 5

public class Sum {

public static void main(String args[]){

double a = 0.0;
double sum = 0.0;

for (int i = 0; i <10; i++){
a = a*10+5;
sum = sum + a;
System.out.println(a);
}
System.out.println("----------------------------\n"+sum);

}
}