Problem: what is the sum of the integers from - 60 to 65 , inclusive ?
Rationale: "in an arithmetic progression , the nth term is given by tn = a + ( n - 1 ) d here tn = 65 , a = - 60 , d = 1 hence , 65 = - 60 + ( n - 1 ) or n = 126 sum of n terms can be calculated by sn = n / 2 ( a + l ) a = first term , l = last term , n = no . of terms sn = 126 * ( - 60 + 65 ) / 2 sn = 126 * 5 / 2 = 315 answer : a"
annotated_formula: divide(multiply(60, 65), const_4)