#include <bits/stdc++.h>
using namespace std;
#define int long long
int l,r,h;
signed main()
{
int t;
cin>>t;
while(t--)
{
int final=0;
cin>>l>>r;
h=r-l+1;
for(int i=l;i<=r;i++)
{
int sum=0,j;
j=i;
if(log10(h)>0 && i%10==0 && r-i>10)
{
while(j/10)
{
sum+=j%10;
j/=10;
sum = (sum % 10) + (sum/10);
}
sum+=j;
sum = (sum % 10) + (sum/10);
final+=(sum*10)+45-(9*sum);
i+=9;
}
else
{
while(j/10)
{
sum+=j%10;
j/=10;
sum = (sum % 10) + (sum/10);
}
sum+=j;
sum = (sum % 10) + (sum/10);
final+=sum;
}
}
cout<<final<<endl;
}
}
