#include <stdio.h>
#include <algorithm>
#include <iostream>
#include <map>
#include <stack>
#include <vector>
#include <memory.h>
#include <set>
#include <string.h>
#include <list>
#include <string>
#include <math.h>
#include <stdlib.h>
#include <queue>
#include <time.h>
#define ll long long
#define forn(i,n) for(int i=0;i<n;++i)
#define rep(i,n) for(int i=1;i<=n;++i)
#define repc(i,l,r) for(int i=l;i<=r;++i)
#define mp(a,b) make_pair(a,b)
#define llf long double
#define pii pair<int,int>
using namespace std;
void solve(){
    ll n, k;
    cin >> n >> k;
    n -= (k - 1)*k / 2;
    if (n < k){
        cout << -1 << endl;
        return;
    }

    ll a = n / k;
    ll b = n%k;
    
    int mod = 1e9 + 7;
    ll res = 1;
    for (int i = 0; i < k; ++i){
        res = res*(a + i + (i + b >= k)) % mod;
    }
    cout << res << endl;
}
int main(){
    //freopen("abc.txt", "r", stdin);
    int T;
    cin >> T;
    while (T--){ 
        solve();
    }
    return 0;
}