#include<bits/stdc++.h>
#define int long long
#define ll __int128
const ll inf=100000000000000000000;
using namespace std;
inline int read(){
	char ch = getchar();int x = 0, f = 1;
	while(ch<'0'||ch>'9'){if(ch == '-') f = -1;ch = getchar();}
	while('0'<=ch && ch <= '9'){x = x*10+ch-'0';ch = getchar();}
	return x*f;
}
inline void write(int x){
	if(x <0)putchar('-'),x =-x;
	if(x >9)write(x /10);
	putchar(x %10+'0');
}
int t,x,k,a[99];
ll f[99][99][2];
signed main(){
	t=read();
	while (t--){
		x=read(),k=read();
		int tx=x,n=0;
		while (tx){ a[++n]=tx%10,tx/=10; } n+=k;
		if (!k){
			int tc=0,i=1;
			while (a[i]==9) tc++,i++;
			putchar('1');
			for (int i=1;i<=tc;i++)
				putchar('0');
			putchar('\n');
			continue;
		} for (int i=1;i<=n+1;i++)
		for (int j=0;j<=k;j++){
			f[i][j][0]=inf;
			f[i][j][1]=inf;
		} f[n+1][0][0]=f[n+1][0][1]=0;
		for (int i=n+1;i>=2;i--)
		for (int j=0;j<=k;j++)
		for (int kk=0;kk<2;kk++){
			if (f[i][j][kk]==inf) continue;
			for (int la=0;la<2;la++)
			for (int s=0;s<=9;s++){
				int tc=s+la+a[i-1];
				int fl=(tc>=10);
				if (kk!=fl) continue;
				if (fl+j>k) continue;
				f[i-1][j+fl][la]=min(f[i-1][j+fl][la],f[i][j][kk]*10+s);
			}
		} 
		int res=f[1][k][0];
		if (res==inf){
			puts("-1");
			continue;
		} write(res);
		putchar('\n');
	}
	return 0;
} 
/*
999999999987654322
999999999987654322
99999999  87654322
*/