import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.*;
import java.io.BufferedReader;
import java.io.InputStreamReader;

public class CodingLegacy {

    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Palindrome solver = new Palindrome();

        int t = in.nextInt();

        for (int i = 0; i < t; i++) {
            solver.solve(i + 1, in, out);
        }
        out.close();
    }

    static class Palindrome {
        static long mod = 1000000007;
        static long max = (long) 1e18;

        void solve(int testNumber, InputReader in, PrintWriter out) {
            long n = in.nextInt();
            long m = in.nextInt();

            long z = n-m;
            long g = m+1;
            long k = z/g;

            long ans = (n*(n+1)/2) - (k*(k+1)/2)*g - (k+1)*(z%g);

            out.println(ans);
        }
    }

    static class Maths{
        static long gcd(long a, long b) {
            if (a == 0)
                return b;
            return gcd(b % a, a);
        }

        public  static long lcm(long a, long b)
        {
            return (a*b)/gcd(a, b);
        }

        public static long factorial(int n){
            long fact = 1;
            for(int i=1;i<=n;i++){
                fact *= i;
            }
            return fact;
        }
    }

    static class Characters{
        public static boolean isVovel(char a){
            return a == 'a' || a == 'e' || a == 'i' || a == 'o' || a == 'u';
        }
    }

    static class Binary {
        public static long numberOfBits(long n){
            long count=0;
            while(n>0){
                count++;
                n >>=1;
            }
            return count;
        }

        public static long numberOfSetBits(long n){
            long count = 0;
            int p = 1;
            while (n>0){
                if((n&p) == 1){
                    count++;
                }
                n >>= 1;
            }
            return count;
        }
    }

    static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;

        InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        int nextInt(){
            return Integer.parseInt(next());
        }

        public Long nextLong(){
            return Long.parseLong(next());
        }
    }
}