#include <bits/stdc++.h>

using namespace std;

using i64 = long long;

int main() {
    cin.tie(0)->sync_with_stdio(false);
    int T;
    cin >> T;
    while (T--) {
    []() {
        i64 x;
        int k;
        cin >> x >> k;
        using i128 = __int128;
        vector<i128> bit(38), pw(38);
        pw[1] = 1;
        for (int i = 1; i < 38; i++) {
            bit[i] = x % 10;
            if (i > 1) pw[i] = pw[i - 1] * 10;
            x /= 10;
        }
        const i128 inf = 1e37;
        vector<vector<array<i128, 2>>> dp(38, vector<array<i128, 2>>(k + 2, {inf, inf})); 
        dp[0][0][0] = 0;
        for (int i = 1; i < 38; i++) {
            for (int j = 0; j <= k; j++) {
                for (int l : {0, 1}) {
                    if (bit[i] + l < 10) {
                        dp[i][j][0] = min(dp[i][j][0], dp[i - 1][j][l]);
                    }
                    if (10 - l - bit[i] < 10 and j >= 1) {
                        dp[i][j][1] = min(dp[i][j][1], dp[i - 1][j - 1][l] + pw[i] * (10 - l - bit[i]));
                    }
                }
            }
        }
        [&](i128 v) {
            if (v == 0) {
                if (bit[1] != 9) cout << 1 << '\n';
                else cout << -1 << '\n';
                return;
            } 
            if (v == inf) {
                cout << -1 << '\n';
                return;
            }
            vector<int> nums;
            while (v) {
                nums.emplace_back((int) (v % 10));
                v /= 10;
            }
            for (auto it = nums.rbegin(); it != nums.rend(); it++) {
                cout << *it;
            }
            cout << '\n';
        }(min(dp[37][k][0], dp[37][k][1]));
    }();
    }
    return 0; 
}