import java.util.*;
import java.io.*;

public class c {

	public static void main(String[] args) {
		JS scan = new JS();
		PrintWriter out = new PrintWriter(System.out);
		int t = scan.nextInt();
		for(int q = 1; q <= t; q++){
			long n = scan.nextInt();
			long m = scan.nextInt();
			long s = n*(n+1)/2;
			if(m == 0){
				out.println(0);
				continue;
			}
			if(m == n){
				out.println(s);
				continue;
			}
			long x = (n-m)/(m+1);
			long c = x*(x+1)/2*(m+1);
			long d = (x+1)*(x+2)/2*((n-m)%(m+1));
			out.println(s-c-d);
//			System.out.println(solve(n,m));
			
//			System.out.println(s-solve(n, m));
		}
		out.flush();
	}
	
	static long ceil(long n, long d){
		return (n+d-1)/d;
	}
	
	static long solve(int n, int k){
		if(k == n) return 0;
		if(k == 0) return n*(n+1)/2;
		return solve((n-1)/2, (k-1)/2)+solve(n/2, k/2);
	}

	static class JS{
		public int BS = 1<<16;
		public char NC = (char)0;
		byte[] buf = new byte[BS];
		int bId = 0, size = 0;
		char c = NC;
		double num = 1;
		BufferedInputStream in;
 
		public JS() {
			in = new BufferedInputStream(System.in, BS);
		}
 
		public JS(String s) throws FileNotFoundException {
			in = new BufferedInputStream(new FileInputStream(new File(s)), BS);
		}
 
		public char nextChar(){
			while(bId==size) {
				try {
					size = in.read(buf);
				}catch(Exception e) {
					return NC;
				}				
				if(size==-1)return NC;
				bId=0;
			}
			return (char)buf[bId++];
		}
 
		public int nextInt() {
			return (int)nextLong();
		}
 
		public long nextLong() {
			num=1;
			boolean neg = false;
			if(c==NC)c=nextChar();
			for(;(c<'0' || c>'9'); c = nextChar()) {
				if(c=='-')neg=true;
			}
			long res = 0;
			for(; c>='0' && c <='9'; c=nextChar()) {
				res = (res<<3)+(res<<1)+c-'0';
				num*=10;
			}
			return neg?-res:res;
		}
 
		public double nextDouble() {
			double cur = nextLong();
			return c!='.' ? cur:cur+nextLong()/num;
		}
 
		public String next() {
			StringBuilder res = new StringBuilder();
			while(c<=32)c=nextChar();
			while(c>32) {
				res.append(c);
				c=nextChar();
			}
			return res.toString();
		}
 
		public String nextLine() {
			StringBuilder res = new StringBuilder();
			while(c<=32)c=nextChar();
			while(c!='\n') {
				res.append(c);
				c=nextChar();
			}
			return res.toString();
		}
 
		public boolean hasNext() {
			if(c>32)return true;
			while(true) {
				c=nextChar();
				if(c==NC)return false;
				else if(c>32)return true;
			}
		}
	}
}
