#include<bits/stdc++.h>
#define ll __int128
using namespace std;
inline ll read(){
	char ch=getchar();
	ll f=1,x=0;
	while(ch<'0'||ch>'9'){
		if(ch=='-')
			f=-f;
		ch=getchar();
	}
	while(ch>='0'&&ch<='9'){
		x=x*10+ch-'0';
		ch=getchar();
	}
	return x*f;
}
inline void work(ll k){
	if(k<0){
		putchar('-');
		k=-k;
	}
	if(k>9)
		work(k/10);
	putchar(k%10+'0');
}
ll t,x,dp[41][41][2];
int k;
ll power(ll a,ll b){
    ll sum=1,k=a;
    while(b){
        if(b&1ll)
            sum*=k;
        k*=k;
        b>>=1ll;
    }
    return sum;
}
int main(){
	t=read();
    while(t--){
        x=read();
        k=read();
        if(!k){
            for(int i=1;i<=20;i++){
                ll now=x/(ll)power(10,i-1)%(ll)10;
                if(now!=9){
                    work((ll)power(10,i-1));
                    break;
                }
            }
            putchar('\n');
            continue;
        }
        memset(dp,64,sizeof(dp));
        dp[0][0][0]=0;
        for(int i=1;i<=37;i++){
            ll now=x/(ll)power(10,i-1)%(ll)10;
            for(int j=0;j<=k;j++){
                dp[i][j][0]=(now==(ll)9?dp[i-1][j][0]:min(dp[i-1][j][0],dp[i-1][j][1]));
                if(j)
                    dp[i][j][1]=(now==(ll)0?dp[i-1][j-1][1]+(ll)9*(ll)power(10,i-1):min(dp[i-1][j-1][1]+(9-now)*(ll)power(10,i-1),dp[i-1][j-1][0]+(10-now)*(ll)power(10,i-1)));
            }
        }
        ll ans=min(dp[20][k][0],dp[20][k][1]);
        if(ans>(ll)1e37)
            work(-1);
        else
            work(ans);
        putchar('\n');
    }
	return 0;
}