#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define endl '\n'
#define fastio ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;

string sn, sm;
int m;
string sa, sb, sc;

string add(string a, string b) {
    reverse(a.begin(), a.end());
    reverse(b.begin(), b.end());
    string c;
    c.resize(max(a.size(), b.size()) + 1);

    a.resize(c.size(), '0');
    b.resize(c.size(), '0');
    int v = 0;
    for (int i = 0; i < c.size(); i++) {
        v += a[i] + b[i] - '0' - '0';
        c[i] = v % 10 + '0';
        v /= 10;
    }
    // while (c.size() > 1 && c.back() == '0') c.pop_back();
    reverse(c.begin(), c.end());
    return c;
}

int smod(string a, int m) {
    reverse(a.begin(), a.end());
    int res = 0;
    for (char c : a) res = (res + c - '0') % m;
    return res;
}

string itos(int x) {
    string res;
    while (x) {
        res += char('0' + x % 10);
        x /= 10;
    }
    reverse(res.begin(), res.end());
    if (!res.size()) res = "0";
    return res;
}

void f(string &sa) {
    reverse(sa.begin(), sa.end());
    while (sa.size() > sn.size()) sa.pop_back();
    reverse(sa.begin(), sa.end());
}

void solve() {
    cin >> sn >> sm;
    // cout << sn << " = "; 
    sn = add(sn, "1");
    // cout << sn << " = "; 
    reverse(sn.begin(), sn.end());
    for (int i = 0; i < 10; i++) sn += '0';
    reverse(sn.begin(), sn.end());


    m = stoi(sm);
    sa = add(sn, itos((m - smod(sn, m)) % m));
    sc = sb = sa;
    bool fb = 0, fc = 0;
    for (int i = sn.size() - sm.size(); i >= 0; i--) {
        string x = sn.substr(i, sm.size());
        if (stoi(x) <= m) {
            if (!fb) {
                sb = sn.substr(0, i) + sm;
                for (int j = sn.size() - sm.size(); j > i; j--) sb += '0';
                fb = 1;
            }
        }
        else {
            if (!fc) {
                sc = add(sn.substr(0, i), "1") + sm;
                for (int j = sn.size() - sm.size(); j > i; j--) sc += '0';
                fc = 1;
            }
        }
    }
    f(sa);
    f(sb);
    f(sc);
    
    string ans = min({sa, sb, sc});
    reverse(ans.begin(), ans.end());
    while (ans.size() > 1 && ans.back() == '0') ans.pop_back();
    reverse(ans.begin(), ans.end());
    
    cout << ans << endl;
}

int main(){
    fastio;
    int T;
    cin >> T;
    while (T--) solve();
    return 0;
}