#include<bits/stdc++.h>
using namespace std;
int n,m;
char str[1000010];
inline bool cmp(string x,string y){
   if(x.size()==y.size())return x<y;
   return x.size()<y.size();
}
inline void prints(string s){
   for(char c:s)putchar(c);puts("");
}
void solve(){
   scanf("%s%d",str+1,&m),n=strlen(str+1);
   int p0=n;
   while(str[p0]=='9')p0--;
   if(!p0){
      n++,str[1]='1';for(int i=2;i<=n;i++)str[i]='0';str[n+1]='\0';
   }else{
      str[p0]++;for(int i=p0+1;i<=n;i++)str[i]='0';
   }
   if(n<9||(n==9&&str[1]=='1')){
      int x;sscanf(str+1,"%d",&x);
      if(x<=m)return printf("%d\n",m),void();
   }
   char mstr[12]{};
   sprintf(mstr,"%d",m);int o=strlen(mstr);
   for(int i=1;i+o-1<=n;i++)if(equal(str+i,str+i+o,mstr)){
      printf("%s\n",str+1);
      return;
   }
   string ans0(str+1);
   int val=0;
   for(int i=1;i<=n;i++)val=(val*10+str[i])%m;
   val=(m-val)%m;
   reverse(begin(ans0),end(ans0));
   for(int i=0;val;i++){
      if(i==ans0.size())ans0+='0';
      val+=ans0[i]-'0';
      ans0[i]=val%10+'0',val/=10;
   }
   int p=max(n-20,1);
   string lst;
   for(int i=n;i>=n-10&&i>=o;i--){
      string w(str+p,str+n+1);
      bool flag=true;
      for(int k=0;k<o;k++){
         if(mstr[k]<str[i-o+1+k]){flag=false;break;}
         if(mstr[k]>str[i-o+1+k])break;
      }
      if(flag){
         for(int k=0;k<o;k++)
         w[w.size()-1-(n-(i-o+1+k))]=mstr[k];
         if(lst.empty()||lst>w)lst=w;
      }
   }
   if(lst.empty())prints(ans0);
   else{
      string ans2(str+1,str+p);
      ans2+=lst;
      prints(min(ans0,ans2,cmp));
   }
}
int main(){
   int T;for(scanf("%d",&T);T--;)solve();
   return 0;
}