#include <cstdio>
#include <algorithm>
#include <vector>

#define lim 225
#define f first.first
#define s first.second
#define pii pair <int, int>
#define mp make_pair

using namespace std;

int calc (int x)
{
    int nr = 0;
    for (; x > 0; x /= 10)
        if (x % 10 == 4) ++nr;
        else if (x % 10 == 7) --nr;

    return nr;
}

bool cmp (pair <pii, int> a, pair <pii, int> b)
{
    return (a.s < b.s);
}

vector < pair <pii, int> > bloc[300];
int nr[50010], ap[10010];
long long ans[50010];

int main ()
{
    //freopen ("file.in", "r", stdin);

    for (int i = 1; i <= 50005; ++i)
        nr[i] = nr[i - 1] + calc (i);

    int q;
    scanf ("%d", &q);

    int nrb = 0;
    for (int i = 1; i <= q; ++i)
    {
        int x, y;
        scanf ("%d %d", &x, &y);

        bloc[x/lim].push_back (mp (mp (x, y), i));

        nrb = max (nrb, x/lim);
    }

    int ri = lim - 1;
    for (int i = 0; i <= nrb; ++i, ri += lim)
    {
        sort (bloc[i].begin (), bloc[i].end (), cmp);

        for (int i = 0; i <= 10005; ++i)
            ap[i] = 0;

        long long rez = 0LL;
        int lst = ri;

        for (auto &it : bloc[i])
        {
            for (int j = lst + 1; j <= it.s; ++j)
            {
                rez += ap[nr[j]];
                ++ap[nr[j]];
            }

            long long crez = rez;
            lst = max (lst, it.s);

            for (int j = it.f - 1; j <= min (it.s, ri); ++j)
            {
                rez += ap[nr[j]];
                ++ap[nr[j]];
            }

            ans[it.second] = rez;
            rez = crez;

            for (int j = it.f - 1; j <= min (it.s, ri); ++j)
                --ap[nr[j]];
        }
    }

    for (int i = 1; i <= q; ++i)
        printf ("%lld\n", ans[i]);

    return 0;
}