include<bits/stdc++.h>

using namespace std; double a[200005]; double s[200005]; double p[200005]; int n,m,l,r; int main(){

scanf("%d%d",&n,&m);
s[0]=1;
p[0]=0;
for(int i=1;i<=n;i++)
{
    scanf("%lf",&a[i]);
    if(a[i]==0)
    {
    	s[i]=1;
    	p[i]=i;
	}
	else
	{
		s[i]=s[i-1]*a[i];
		p[i]=p[i-1];
	}
    //s[i]=s[i-1]*a[i];
}
while(m--)
{
	scanf("%d%d",&l,&r);
	if(p[r]>=l)
	{
		double d=0;
		printf("%.2lf\n",d);
		continue;
	}
	double sum=0;
	sum=s[r]/s[l-1];
	printf("%.2lf\n",sum);
}
return 0;

}