#include <bits/stdc++.h>
using namespace std;
const long long M = 1000000007;
const int NSIZE = 1050;
const int no = 1049;
long long K;
long long dp[NSIZE][NSIZE][2];
char str[NSIZE];
char *s;
long long calc(int pos, int prepos, int ext, bool flag) {
  if (pos == -1) return ext;
  if (flag == false && dp[pos][prepos][ext] != -1) return dp[pos][prepos][ext];
  if (flag) {
    int top = s[pos] - '0';
    long long ans = 0;
    for (int c = 0; c <= top; c++)
      if (c == 4 || c == 7) {
        if (prepos == no)
          ans += calc(pos - 1, pos, ext, c == top);
        else if (prepos - pos <= K)
          ans += calc(pos - 1, pos, 1, c == top);
        else
          ans += calc(pos - 1, pos, ext, c == top);
        ans %= M;
      } else {
        ans += calc(pos - 1, prepos, ext, c == top);
        ans %= M;
      }
    return ans;
  } else {
    long long &ans = dp[pos][prepos][ext];
    ans = 0;
    for (int c = 0; c <= 9; c++)
      if (c == 4 || c == 7) {
        if (prepos == no)
          ans += calc(pos - 1, pos, ext, 0);
        else if (prepos - pos <= K)
          ans += calc(pos - 1, pos, 1, 0);
        else
          ans += calc(pos - 1, pos, ext, 0);
        ans %= M;
      } else {
        ans += calc(pos - 1, prepos, ext, 0);
        ans %= M;
      }
    return ans;
  }
}
long long gao(char *sin) {
  s = sin;
  int len = strlen(s);
  reverse(s, s + len);
  long long ans = 0;
  for (int c = '0'; c <= s[len - 1]; c++)
    if (c == '4' || c == '7')
      ans = (ans + calc(len - 2, len - 1, 0, c == s[len - 1])) % M;
    else
      ans = (ans + calc(len - 2, no, 0, c == s[len - 1])) % M;
  return ans;
}
char A[2000], B[2000];
long long chk(char *s) {
  int pre = -1;
  for (int i = 0; s[i]; i++)
    if (s[i] == '4' || s[i] == '7') {
      if (pre != -1 && i - pre <= K) return 1;
      pre = i;
    }
  return 0;
}
int main() {
  memset(dp, -1, sizeof(dp));
  int T;
  cin >> T >> K;
  for (int ii = 0; ii < T; ii++) {
    cin >> A >> B;
    cout << ((gao(B) - gao(A) + chk(A)) % M + M) % M << endl;
  }
  return 0;
}
