#include <bits/stdc++.h>
#define int long long
using namespace std;
const int N = 20;
int f[N][N][2];
int p[N];
void init() {
  p[0] = 1;
  for (int i = 1; i < N; i ++ )
    p[i] = (p[i - 1] << 3ll) + (p[i - 1] << 1ll);
}
inline int solve(int x, int k) {
  if (!k) {
    int ans = 1;
    while (x % (ans * 10) / ans == 9) ans *= 10;
    return ans;
  }
  memset(f, 0x3f, sizeof f);
  f[0][0][0] = 0;
  for (int i = 1; i < N; i ++ )
    for (int j = 0; j <= k; j ++ ) {
      f[i][j][0] =min(f[i][j][0], f[i - 1][j][0]);
      if (x % p[i] / p[i - 1] < 9) f[i][j][0] = min(f[i][j][0], f[i - 1][j][1]);
      if (j) {
        f[i][j][1] = min(f[i][j][1], f[i - 1][j - 1][1] + p[i - 1] * (10 - x % p[i] / p[i - 1] - 1));
        if (x % p[i] / p[i - 1]) f[i][j][1] = min(f[i][j][1], f[i - 1][j - 1][0] + p[i - 1] * (10 - x % p[i] / p[i - 1]));
      }
    }
  return f[19][k][0] == 0x3f3f3f3f3f3f3f3f ? -1 : f[19][k][0];
}
int t, x, k;
signed main() {
  init();
  cin >> t;
  while (t -- ) {
    cin >> x >> k;
    string s;
    while (x % 10 == 0) x /= 10, s += '0';
    int res = solve(x, k);
    cout << res;
    if (res != -1) cout << s;
    cout << '\n';
  }
}