#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <cmath>
#include <complex>
#include <deque>
#include <forward_list>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iostream>
#include <limits>
#include <list>
#include <map>
#include <memory>
#include <numeric>
#include <optional>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <tuple>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using u64 = std::uint64_t;

constexpr u64 MAX = std::numeric_limits<u64>::max();

void solve() {
    u64 X;
    int K;
    std::cin >> X >> K;
    std::string S = std::to_string(X);
    std::vector dp(19, std::vector(19, std::vector(2, std::vector(2, MAX))));
    dp[0][0][0][0] = 0;
    u64 ten = 1;
    u64 now = X;
    for(int i = 0; i < 18; i++) {
        u64 num = now % 10;
        now /= 10;
        for(int k = 0; k < 19; k++) {
            for(int c = 0; c < 2; c++) {
                for(int z = 0; z < 2; z++) {
                if(dp[i][k][c][z] == MAX) continue;
                u64 x = num + c;
                if(k + 1 < 19 && x > 0) {
                    dp[i + 1][k + 1][1][z || (10 - x) > 0] = std::min(dp[i + 1][k + 1][1][z || (10 - x) > 0], dp[i][k][c][z] + ten * (10 - x));
                }
                if(x <= 9) {
                    dp[i + 1][k][0][z] = std::min(dp[i + 1][k][0][z], dp[i][k][c][z]);
                }
                if(x <= 8) {
                    dp[i + 1][k][0][1] = std::min(dp[i + 1][k][0][1], dp[i][k][c][z] + ten * 1);
                }
                }
            }
        }
        ten *= 10;
    }
    u64 ans = std::min(dp[18][K][0][1], dp[18][K][1][1]);
    if(ans == MAX) {
        std::cout << -1 << std::endl;
    }
    else {
        std::cout << ans << std::endl;
    }
}

int main() {
    int T;
    std::cin >> T;
    while(T--) {
        solve();
    }
}