#include<bits/stdc++.h>
using namespace std;

#define ll long long

int t,k,len;
string a;
int num[25];
int ans;

void pre()
{
    for(int i=len;i>=1;--i)
    {
        int j=i-1;
        while(a[j]=='9')
        {
            j--;
            if(j==0) break;
        }
        num[i]=i-j;
    }
}

string change(int anss)
{
    string chan = "";
    int judge=0;
    for(int i=0;i<len;++i)
    {
        if((anss & (1<<i)) != 0)
        {
            chan = (char)((10-(a[len-i]-'0')-judge)+'0')+chan;
            judge=1;
        }
        else 
        {
            chan = "0"+chan;
            judge=0;
        }
    } 
    int cnt=0;
    while(chan[cnt]=='0')
    {
        cnt++;
    }
    chan = chan.substr(cnt,chan.length()-cnt);
    return chan;
}

void dfs(int now, int tot, int now_ans, bool judge) // now是当前位置，tot是进位数
{
    if(now<0 || tot>k) return;
    if(tot==k) 
    {
        ans=min(ans,now_ans);
        return;
    }
    if(now==0) return;
    dfs(now-1,tot,now_ans,0);
    if(a[now]=='0' && judge==0) return;
    int now_ans2=now_ans;
    now_ans2 |= (1<<(len-now));
    dfs(now-num[now],tot+num[now],now_ans2,1);
    return;
}

int main()
{
    cin>>t;
    while(t--)
    {
        string str;
        cin>>str>>k;
        a="0"+str;
        len = str.length();
        pre();
        ans = (1<<20)-1;
        dfs(len,0,0,0);

        string real_ans = change(ans);
        if(real_ans=="") real_ans="1";
        for(int i=1;i<=k-len;++i)
        {
            real_ans = "9"+real_ans;
        }
        cout<<real_ans<<endl;
    }
    // system("pause");
    return 0;
}
/*
1
990099 5

*/