#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define per(i,a,b) for(int i=(a);i>=(b);i--)
#define op(x) ((x&1)?x+1:x-1)
#define odd(x) (x&1)
#define even(x) (!odd(x))
#define lc(x) (x<<1)
#define rc(x) (lc(x)|1)
#define lowbit(x) (x&-x)
#define mp(x,y) make_pair(x,y)
typedef long long ll;
typedef unsigned long long ull;
typedef double db;
using namespace std;
typedef __int128 i128;

const ll MAXN = 50,M = 36;
const i128 INF = 1e37;
void tomin(i128& x,i128 y){x = min(x,y);}

ll T,n,k,a[MAXN];

i128 dp[MAXN][MAXN][2],pw[MAXN];

void outp(i128 a){
	if(a<10){
		cout<<(int)(a);
		return;
	}
	outp(a/10);
	cout<<(int)(a%10);
}

void solve(){
	cin>>n>>k;

	ll num = n;
	rep(i,1,M)a[i] = num%10,num /= 10;

	rep(i,0,M)rep(j,0,k)rep(c,0,1)dp[i][j][c] = INF;
	dp[0][0][0] = 0;
	rep(i,1,M){
		rep(j,0,k)rep(c,0,1)if(dp[i-1][j][c] != INF){
			i128 val = dp[i-1][j][c];

			ll x = a[i]+c;
			if(x==10){
				tomin(dp[i][j+1][1],val);
			}else{
				//不进位
				tomin(dp[i][j][0],val);
				//进位
				if(x){
					ll y=10-x;
					tomin(dp[i][j+1][1],val+y*pw[i]);
				}
			}
		}
	}
	ll R = min(dp[M][k][0],dp[M][k][1]);
	if(R == INF){
		cout<<"-1\n";
	}else{
		if(R==0){ //corner case
			assert(k==0);
			rep(i,1,M)if(a[i] != 9){
				outp(pw[i]);cout<<"\n";
				return;
			}	
			assert(0);
			return;
		}

		outp(R);cout<<"\n";
	}
}

int main(){
	//freopen("in.in","r",stdin);
	//freopen("out.out","w",stdout);

	ios::sync_with_stdio(false);cin.tie(0);

	pw[1] = 1;rep(i,2,M)pw[i] = pw[i-1] * 10;

	cin>>T;
	while(T--)solve();

    return 0;
}