#include <iostream>
#include <cmath>
#include <string>


using namespace std;

int main(){

    int t; cin>>t;
    while(t>0){t--;
        double l,r; cin>>l>>r;
        double sum=(r-l+1)*((r+l)/2);
        cout<<(long long)sum<<endl;
    }

    return 0;
}