//c++ code

include

using namespace std;

define endl '\n'

define ig cin.ignore()

define GET_FASTER ios_base::sync_with_stdio(false); cin.tie(NULL)

typedef long long int ll; const ll mx= LLONG_MAX; const ll mn= LLONG_MIN; const ll MOD= 1e9+7; bool descending_order(int x, int y){return x>y;}

long long nth_term(long long n){ return (n+(n*n))/2; }

int main(){

GET_FASTER;

int t;
cin>> t;

while(t--){
    long long n,m;
    cin>> n>> m;

    long long rem= n %m;
    long long div= n/m;
    long long tem= m-1;

    long long result;

    result = ((nth_term(tem)*div)+ nth_term(rem));

    cout<< result<< endl;

}


return 0;

}