link

#include <bits/stdc++.h>
#define ull unsigned long long
using namespace std;
ull l,r;
int main()
{
    int t;
    cin>>t;
    while(t--)
    {
        cin>>l>>r;
        ull c=r-l;
        if(10>=c)
        {
            ull sum=0;
            for(int i=l;i<=r;i++)
            {
                sum+=i;
            }
            cout<<sum%9<<endl;
            continue;
        }
        int xy=floor(c/(9.0));
        int e=r-(9*xy);
        ull x=(((l+e)*(e-l+1))/2);
        cout<<x%9<<endl;
    }
    return 0;
}