#include<bits/stdc++.h>
using namespace std;using ll=long long;const ll inf=3e18;
int dp[30][30][2];
struct S
{
	vector<vector<vector<ll>>>dp;
	void solve()
	{
		int c0=0,di[19];ll bas=1;
		dp.resize(20,vector<vector<ll>>(20,vector<ll>(2,inf)));
		ll x,k;cin>>x>>k;
		if(k==18)
		{
			ll bs=1;for(int i=1;i<=18;i++)bs*=10;cout<<bs-x;
			while(c0--)cout<<'0';cout<<'\n';return;
		}
		else if(k==0)
		{
			if(c0){cout<<"1\n";return;}ll res=1;
			while(x%10==9)x/=10,res*=10;cout<<res<<'\n';return;
		}
		while(x%10==0)x/=10,c0++;dp[0][0][0]=0;
		for(int i=1;i<=18;i++)di[i]=x%10,x/=10;
		for(int i=1;i<=18;i++,bas*=10)
		{
			for(int j=0;j<=18;j++)
			{
				dp[i][j][0]=min(dp[i][j][0],dp[i-1][j][0]);
				if(di[i]!=9)dp[i][j][0]=min(dp[i][j][0],dp[i-1][j][1]);
				dp[i][j+1][1]=min(dp[i][j+1][1],dp[i-1][j][1]+bas*(9-di[i]));
				if(di[i]!=0)dp[i][j+1][1]=min(dp[i][j+1][1],dp[i-1][j][0]+bas*(10-di[i]));
				//cout<<"now"<<i<<"over"<<j<<"L"<<0<<":"<<dp[i][j][0]<<'\n';
				//cout<<"now"<<i<<"over"<<j<<"L"<<1<<":"<<dp[i][j][1]<<'\n';
			}
		}		
		ll res=dp[18][k][0];cout<<res;while(c0--)cout<<'0';cout<<'\n';return;
	}
};
int main()
{
	//freopen("3.in","r",stdin);
	//cout<<fixed<<setprecision(12);
	ios::sync_with_stdio(0);cin.tie(0);
	int t=1;cin>>t;
	//clock_t a=clock();
	while(t--){S SS;SS.solve();}
	//cout<<"Time:"<<double(clock()-a)<<'\n';
}