#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <cstring>
#include <map>
#include <iomanip>
#include <cstdio>
#define mp make_pair
#define pb push_back
#define LL long long
#define inf 2e9
#define zeros x^(x-1)&x
#define Nmax 50001
using namespace std;

int s,n,rez[Nmax];
struct query{
    int l,r,poz;
}Q[Nmax];

bool comp(query a,query b)
{
    if (a.l / s != b.l / s)
        return a.l / s < b.l / s;
    return a.r > b.r;
}

int calc47(int a,int b,int cum)
{
    int rez = 0,i,salt;
    if (cum==2)
    {
        i = a;
        while (i%10!=4 && i%10!=7 && i<=b)
            i++,rez++;
        if (i%10==4)
        {
            i+=3;
            salt = 7;
        }
        else
        {
            i+=7;
            salt = 3;
        }
        for (;i<=b;i+=10)
        {
            rez += min(salt,b-i+1);
        }
        return rez;
    }
    else
    {
        i = b;
        while (i%10!=4 && i%10!=7 && i>=a)
            i--,rez++;
        if (i%10==4)
        {
            i-=7;
            salt = 3;
        }
        else
        {
            i-=3;
            salt = 7;
        }
        for (;i>=a;i-=10)
        {
            rez += min(salt,i-a+1);
        }
        return rez;
    }
}

int main()
{
    cin.sync_with_stdio(false);
    cin>>n;
    for (int i=1;i<=n;i++)
    {
        cin>>Q[i].l>>Q[i].r;
        Q[i].poz = i;
    }

    s = sqrt(n);
    sort(Q+1,Q+n+1,comp);

    int st = 1,dr = 0;
    LL nr = 0;
    for (int i=1;i<=n;i++)
    {
        while (dr<Q[i].r)
        {
            dr++;
            nr += calc47(st,dr,1);
        }
        while (dr>Q[i].r)
        {
            nr -= calc47(st,dr,1);
            dr--;
        }
        while (st<Q[i].l)
        {
            nr -= calc47(st,dr,2);
            st++;
        }
        while (st>Q[i].l)
        {
            st--;
            nr += calc47(st,dr,2);
        }
        rez[Q[i].poz] = nr;
    }
    for (int i=1;i<=n;i++)
        cout<<rez[i]<<'\n';

    return 0;
}