#include <bits/stdc++.h>

#define lep(i, l, r) for(int i = (l); i <= (r); i ++)
#define rep(i, l, r) for(int i = (l); i >= (r); i --)
#define debug(...) fprintf (stderr, __VA_ARGS__)

using std :: cin;
using std :: cout;
using std :: endl;
using std :: cerr;
using i64 = long long;

const int P = 998244353;
inline int mod(int x) { return x + (x >> 31 & P); }
inline void sub(int &x, int y) { x = mod(x - y); }
inline void pls(int &x, int y) { x = mod(x + y - P); }
inline int add(int x, int y) { return mod(x + y - P); }
inline int dec(int x, int y) { return mod(x - y); }
inline int power(int x, int k) {
	int res = 1; if (k < 0) k += P - 1;
	while (k) { if (k & 1) res = 1ll * res * x % P; x = 1ll * x * x % P; k >>= 1; }
	return res;
}

__int128 dp[44][22][2]; // 第几位 进位次数 当前位有没有进位
int s[44], top;
__int128 pw[64];
int K;

__int128 dfs (int now, int cnt, int o) {
	if (dp[now][cnt][o] != -1) return dp[now][cnt][o];
	if (cnt > K) return 1e38;
	if (now > 37) {
		if (cnt == K) return 0;
		return 1e38;
	}
	__int128 ans = 1e38;
	for (int i = 0; i <= 9; i ++) {
		int ok = (i + o + s[now]) >= 10;
		ans = std :: min (ans, dfs (now + 1, cnt + ok, ok) + i * pw[now - 1]);
	}
	return dp[now][cnt][o] = ans;
} 

void print (__int128 x) {
	if (x) {
		print (x / 10);
		cout << (int) (x % 10);
	}
}

void solve() {
	memset (dp, -1, sizeof (dp));
	i64 n;
	pw[0] = 1;
	for (int i = 1; i <= 50; i ++) pw[i] = pw[i - 1] * 10;
	cin >> n >> K;

	if (K == 0) {
		__int128 now = 1;
		for (int i = 1; i <= 20; i ++) {
			if (n / now % 10 != 9) {
				print (now);
				cout << endl;
				return ;
			}
			now *= 10;
		}
		assert (0);
		return ;
	}

	top = 0;
	while (n) s[++ top] = n % 10, n /= 10;
	s[top + 1] = s[top + 2] = 0;
	__int128 ans = dfs (1, 0, 0);
	if (ans >= 1e38) {
		cout << -1 << endl;
	} else print (dfs (1, 0, 0));
	cout << endl;
}

int main() {
	std :: ios :: sync_with_stdio(false);
	int Case; cin >> Case;
	while (Case --) solve();
	return 0;
}