from sys import stdin, stdout
import math,sys,heapq
from itertools import permutations, combinations
from collections import defaultdict,deque,OrderedDict
from os import path
import random
import bisect as bi
def yes():print('YES')
def no():print('NO')
if (path.exists('input.txt')): 
    #------------------Sublime--------------------------------------#
    sys.stdin=open('input.txt','r');sys.stdout=open('output.txt','w');
    def I():return (int(input()))
    def In():return(map(int,input().split()))
else:
    #------------------PYPY FAst I/o--------------------------------#
    def I():return (int(stdin.readline()))
    def In():return(map(int,stdin.readline().split()))
#sys.setrecursionlimit(1500)
def dict(a):
    d={} 
    for x in a:
        if d.get(x,-1)!=-1:
            d[x]+=1
        else:
            d[x]=1
    return d
def find_gt(a, x):
    'Find leftmost value greater than x'
    i = bi.bisect_left(a, x)
    if i != len(a):
        return i
    else:            
        return -1

def su(n):
    return (((n)*(n+1))//2)

def gcd(a,b):
    if b==0:
        return a
    return gcd(b,a%b)
def main():
    try:
        n,m=In()
        t=su(n)
        #print(t)
        z=n-m
        g=m+1
        k=z//g
        ans=su(n)-(su(k)*g)-(k+1)*(z%g)
        print(ans)

    except:
        pass
        
M = 998244353
P = 1000000007
 
if __name__ == '__main__':
    for _ in range(I()):main()
    #for _ in range(1):main()