#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
int gnn[20];
int dp[1010][1010][2], K;
int B, m;
void upt(int &x) {
  if (x >= mod) x -= mod;
}
int dfs(int num, int lim, int lst, int cop) {
  if (!lim && dp[num][lst][cop] != -1) return dp[num][lst][cop];
  if (!num) return cop;
  int ans = 0;
  int k = lim ? gnn[num] : 9;
  for (int i = 0; i <= k; i++)
    ans += dfs(num - 1, i == k && lim, (i == 4 || i == 7) ? num : lst,
               cop || (lst && (i == 4 || i == 7) && (lst - num <= K))),
        upt(ans);
  if (!lim) dp[num][lst][cop] = ans;
  return ans;
}
char S[1010];
int solve(int mi) {
  int len = strlen(S + 1);
  for (int i = 1, j = len; i <= len; i++, j--) gnn[i] = S[j] - '0';
  if (mi) {
    gnn[1]--;
    for (int i = 1; i <= len; i++) {
      if (gnn[i] < 0) gnn[i] += 10, gnn[i + 1]--;
    }
    if (!gnn[len]) len--;
  }
  return dfs(len, 1, 0, 0);
}
int main() {
  memset(dp, -1, sizeof(dp));
  int T;
  scanf("%d%d", &T, &K);
  while (T--) {
    scanf("%s", S + 1);
    int ans = -solve(1);
    scanf("%s", S + 1);
    ans += solve(0);
    if (ans < 0) ans += mod;
    printf("%d\n", ans);
  }
  return 0;
}
