the sum of all the integers a such that - 26 < a < 24 is
easy one - - 25 , - 24 , - 23 , - 22 , . . . . . . - 10 , 1 , 2 . . . . , 22 , 23 cancel everyhitng and we ' re left with - - 25 and - 24 a = - 49 . d is the answer .
add(add(negate(26), const_1), add(add(negate(26), const_1), const_1))