# -*- coding: utf-8 -*-
import bisect
import heapq
import math
import random
import sys
from collections import Counter, defaultdict, deque
from decimal import ROUND_CEILING, ROUND_HALF_UP, Decimal
from functools import lru_cache, reduce
from itertools import combinations, combinations_with_replacement, product, permutations
from operator import add, mul, sub

sys.setrecursionlimit(100000)
input = sys.stdin.readline  # -*- coding: utf-8 -*-

sys.setrecursionlimit(100000)
input = sys.stdin.readline
INF = 2**62-1


def read_int():
    return int(input())


def read_int_n():
    return list(map(int, input().split()))


def read_float():
    return float(input())


def read_float_n():
    return list(map(float, input().split()))


def read_str():
    return input().strip()


def read_str_n():
    return list(map(str, input().split()))


def error_print(*args):
    print(*args, file=sys.stderr)


def mt(f):
    import time

    def wrap(*args, **kwargs):
        s = time.time()
        ret = f(*args, **kwargs)
        e = time.time()

        error_print(e - s, 'sec')
        return ret

    return wrap


def slv(N, M):
    if M == 0:
        return 0
    if M == N:
        return ((N+1) * N ) // 2

    ans = ((N+1) * N) // 2
    r = N - M
    d = r // (M+1)
    e = r % (M+1)
    if d != 0:
        ans -= (((d+2) * (d+1)) // 2) * (e)
        ans -= (((d+1) * d) // 2) * (M+1 - e)
    else:
        ans -= r
    return ans




def main():
    T = read_int()
    for _ in range(T):
        N, M = read_int_n()
        print(slv(N, M))


if __name__ == "__main__":
    main()
