#include <bits/stdc++.h>
using namespace std;
const long long M = 1000000007;
int n, t, d, last;
bool flag;
long long res, A;
long long f[2005][2005], s[2005][2005], g[2005], B[2005];
char a[2005], b[2005];
int c[2005];
long long calc(char a[]) {
  n = strlen(a + 1);
  if (!n) return 0;
  last = 0, flag = 0, res = 0;
  for (int i = 1; i <= n; ++i) {
    for (int j = 0; j < a[i] - '0'; ++j) {
      if (flag)
        res += B[n - i];
      else if (j == 4 || j == 7) {
        if (last && i - last <= d)
          res += B[n - i];
        else
          res += s[n - i][max(n + 1 - i - d, 1)] + g[n - i];
      } else if (last)
        res += s[n - i][max(n + 1 - last - d, 1)] + g[n - i];
      else
        res += g[n - i];
    }
    if (a[i] == '4' || a[i] == '7') {
      if (last && i - last <= d) flag = 1;
      last = i;
    }
    res %= M;
  }
  if (flag) ++res;
  return res;
}
int main() {
  scanf("%d%d", &t, &d);
  B[0] = 1;
  for (int i = 1; i <= 1005; ++i) B[i] = B[i - 1] * 10 % M;
  f[0][0] = 1;
  for (int i = 0; i <= 1005; ++i) {
    g[i + 1] = g[i] * 10 % M;
    for (int j = i; j >= 0; --j) s[i][j] = (s[i][j + 1] + f[i][j]) % M;
    for (int j = 0; j <= i; ++j)
      if (f[i][j]) {
        for (int k = 0; k < 10; ++k) {
          if (k == 4 || k == 7) {
            if (j && i + 1 - j <= d)
              g[i + 1] = (g[i + 1] + f[i][j]) % M;
            else
              f[i + 1][i + 1] = (f[i + 1][i + 1] + f[i][j]) % M;
          } else
            f[i + 1][j] = (f[i + 1][j] + f[i][j]) % M;
        }
      }
  }
  for (; t--;) {
    if (t == 1) {
      int xp = 0;
    }
    scanf("%s%s", a + 1, b + 1);
    A = calc(b);
    c[0] = 0;
    for (int i = 1; i <= strlen(a + 1); ++i)
      c[++c[0]] = a[strlen(a + 1) - i + 1] - '0';
    --c[1];
    for (int i = 1; i <= c[0]; ++i)
      if (c[i] < 0) c[i] += 10, c[i + 1]--;
    for (; c[0] && !c[c[0]]; --c[0])
      ;
    if (c[0]) {
      memset(a, 0, sizeof(a));
      int l = 0;
      for (int i = c[0]; i >= 1; --i) a[++l] = c[i] + '0';
      A -= calc(a);
    }
    printf("%I64d\n", ((A % M) + M) % M);
  }
  return 0;
}
