#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
inline int my_getchar() {
  static char buf[1048576];
  static int s = 1048576;
  static int e = 1048576;
  if (s == e && e == 1048576) {
    e = fread(buf, 1, 1048576, stdin);
    s = 0;
  }
  if (s == e) {
    return EOF;
  }
  return buf[s++];
}
inline void rd(int &x) {
  int k;
  int m = 0;
  x = 0;
  for (;;) {
    k = my_getchar();
    if (k == '-') {
      m = 1;
      break;
    }
    if ('0' <= k && k <= '9') {
      x = k - '0';
      break;
    }
  }
  for (;;) {
    k = my_getchar();
    if (k < '0' || k > '9') {
      break;
    }
    x = x * 10 + k - '0';
  }
  if (m) {
    x = -x;
  }
}
inline int rd_int(void) {
  int x;
  rd(x);
  return x;
}
struct MY_WRITER {
  char buf[1048576];
  int s;
  int e;
  MY_WRITER() {
    s = 0;
    e = 1048576;
  }
  ~MY_WRITER() {
    if (s) {
      fwrite(buf, 1, s, stdout);
    }
  }
};
MY_WRITER MY_WRITER_VAR;
void my_putchar(int a) {
  if (MY_WRITER_VAR.s == MY_WRITER_VAR.e) {
    fwrite(MY_WRITER_VAR.buf, 1, MY_WRITER_VAR.s, stdout);
    MY_WRITER_VAR.s = 0;
  }
  MY_WRITER_VAR.buf[MY_WRITER_VAR.s++] = a;
}
inline void wt_L(char a) { my_putchar(a); }
inline void wt_L(int x) {
  int s = 0;
  int m = 0;
  char f[10];
  if (x < 0) {
    m = 1;
    x = -x;
  }
  while (x) {
    f[s++] = x % 10;
    x /= 10;
  }
  if (!s) {
    f[s++] = 0;
  }
  if (m) {
    my_putchar('-');
  }
  while (s--) {
    my_putchar(f[s] + '0');
  }
}
inline void wt_L(long long x) {
  int s = 0;
  int m = 0;
  char f[20];
  if (x < 0) {
    m = 1;
    x = -x;
  }
  while (x) {
    f[s++] = x % 10;
    x /= 10;
  }
  if (!s) {
    f[s++] = 0;
  }
  if (m) {
    my_putchar('-');
  }
  while (s--) {
    my_putchar(f[s] + '0');
  }
}
template <class T>
inline int sod_L(T n) {
  int res = 0;
  while (n) {
    res += n % 10;
    n /= 10;
  }
  return res;
}
template <class S, class T>
inline S chmin(S &a, T b) {
  if (a > b) {
    a = b;
  }
  return a;
}
int N;
int K;
long long mn[200][200];
int main() {
  int d, hCmBdyQB, i;
  long long v;
  for (i = (0); i < (200); i++) {
    int j;
    for (j = (0); j < (200); j++) {
      mn[i][j] = 4611686016279904256LL;
    }
  }
  for (i = (0); i < (1000); i++) {
    chmin(mn[sod_L(i)][sod_L(i + 1)], i);
  }
  for (d = (0); d < (17); d++) {
    int f;
    for (f = (1); f < (10); f++) {
      int mask;
      for (mask = (0); mask < (1 << d); mask++) {
        v = f;
        for (i = (0); i < (d); i++) {
          if (((mask) & (1 << (i)))) {
            v = v * 10 + 9;
          } else {
            v = v * 10 + 8;
          }
        }
        chmin(mn[sod_L(v)][sod_L(v + 1)], v);
      }
    }
  }
  int V9aVTaxx = rd_int();
  for (hCmBdyQB = (0); hCmBdyQB < (V9aVTaxx); hCmBdyQB++) {
    int i;
    int x;
    int y;
    int t;
    long long res = 4611686016279904256LL;
    rd(N);
    rd(K);
    for (i = (0); i < (10); i++) {
      int j;
      t = x = y = 0;
      for (j = (0); j < (K + 1); j++) {
        if (i + j >= 10) {
          y++;
        } else {
          x++;
        }
        t += (i + j) % 10;
      }
      for (j = (0); j < (200); j++) {
        int k;
        for (k = (0); k < (200); k++) {
          if (t + x * j + y * k == N && mn[j][k] < 4611686016279904256LL) {
            chmin(res, mn[j][k] * 10 + i);
          }
        }
      }
    }
    if (res == 4611686016279904256LL) {
      wt_L(-1);
      wt_L('\n');
    } else {
      wt_L(res);
      wt_L('\n');
    }
  }
  return 0;
}
