#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define eb emplace_back
//mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
#define mod 998244353
#define int __int128
#define inf 0x3f3f3f3f
#define INF ((int)1e19)
inline int read()
{
	char ch=getchar(); int nega=1; while(!isdigit(ch)) {if(ch=='-') nega=-1; ch=getchar();}
	int ans=0; while(isdigit(ch)) {ans=ans*10+ch-48;ch=getchar();}
	if(nega==-1) return -ans;
	return ans;
}
void print(vector<int> x){for(int i=0;i<(int)x.size();i++) printf("%d%c",x[i]," \n"[i==(int)x.size()-1]);}
int pw[105];
void work()
{
	int n=read(),k=read();
	vector<int> s;
	while(n)
	{
		s.push_back(n%10);
		n/=10;
	}
	while((int)s.size()<36) s.push_back(0);
	int mn=0;
	if(k==0)
	{
		int pw=1;
		for(int i=0;;i++)
		{
			if(s[i]!=9)
			{
				printf("%lld\n",(long long)pw);
				return ;
			}
			pw*=10;
		}
	}
	vector<int> ts=s;
	int tk=k;
	for(int i=0;k>0;i++)
	{
		// if(s[i]==9)
		{
			int j=i;
			while(s[j+1]==9) j++;
			int gv=min(j-i+1,j-i+1);
			mn+=(10-s[j-gv+1])*pw[j-gv+1];
			s[j+1]++;
			i=j;
			k-=gv;
		}
		// else
		// {
			// k--;
			// mn+=(10-s[i])*pw[i];
			// s[i+1]++;
		// }
	}
	int adi=-k;
	s=ts,k=tk;
	int ans=0;
	for(int i=0;k>0;i++)
	{
		// if(s[i]==9)
		{
			int j=i;
			while(s[j+1]==9) j++;
			int ngo=min(adi,j-i+1);
			adi-=ngo;
			int gv=j-i+1-ngo;
			if(gv) ans+=(10-s[j-gv+1])*pw[j-gv+1];
			s[j+1]++;
			i=j;
			k-=gv;
		}
		// else
		// {
			// k--;
			// mn+=(10-s[i])*pw[i];
			// s[i+1]++;
		// }
	}
	printf("%lld\n",(long long)ans);
}
signed main()
{
	pw[0]=1; for(int i=1;i<=19;i++) pw[i]=pw[i-1]*10;
	int T=read(); while(T--) work();
	return 0;
}