#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#include<cmath>
using namespace std;


__int64 num[2*100000];
const int MM =(int) 1e9+7;
int main ()
{
    int T;
    cin>>T;
    while(T--)
    {
        int n, k;
        cin>>n>>k;
        __int64 sum = (__int64)k*(k+1)/2;
        n-=sum;
        if(n<0)
        {
            cout<<-1<<endl;
            continue;
        }
        for(int i = 1; i <= k; i++)
        {
            num[i] = (__int64)i+(n/k);
            num[i]%=MM;
        }
        int temp = n%k;
        for(int i = k; i > k-temp; i--)
        {
            num[i]++;
            num[i]%=MM;
        }
        sum = 1;
        for(int i = 1; i <= k; i++)
        {
            sum *= num[i];
            sum%=MM;
        }
        printf("%I64d\n", sum);
    }
    return 0;
}