#include<bits/stdc++.h>
using namespace std;
#define ull unsigned long long
ull l,r,q;
ull asd[10];
int main()
{
    freopen("xiaokai.in","r",stdin);
    freopen("xiaokai.out","w",stdout);
    cin>>q;
    while(q!=0)
    {
    q--;    
    cin>>l>>r;
    ull t=l;
    for(int i=1;i<=9&&t<=r;++i)
    {
        asd[i]=(asd[i-1]+t%9)%9;
        t++;    
    }        
    if(r-l<=9)
    {
        cout<<asd[r-l+1]<<endl;
        continue;
    }
    while(t+9<=r)
        t+=9;
    cout<<asd[r-t+1]<<endl;
    }
    return 0;
}