algebra
posted by Annie .
The sum of the first n counting numbers 1 + 2 + 3 + 4 + 5 ... + n is given by S = n/2(1 + n).
a) Find the sum of the numbers 14 to 40 inclusive
Answer is 729. But i don't get why.
Someone explain what the qestion means by "inclusive" please ><!

you want the sum of the numbers from 14 to 40 inclusive (the inclusive means that the number 40 is to be included in the count)
the formula you have given only works if we start at 1
so why not find the sum from 1 to 40, then the sum from 1 to 13 and subtract that.
Wouldn't you end up with only those from 14 to 40 added up??
Let me know what you got this time.
Respond to this Question
Similar Questions

Math riddle
nine odd numbers have a sum of 243.find the sum of the first and last numbers in a set of numbers. hint:if three numbers when added equals twelve then represent it by adding n+()n+1. 
Math riddle
nine odd numbers have a sum of 243.find the sum of the first and last numbers in a set of numbers. hint:if three numbers when added equals twelve then represent it by adding n+()n+1. no one cares...durrr.... 
algebra
The sum of the swuares of the first n counting numbers: 1² + 2² + 3² + 4² + 5² + 6² + ... +n² is given by the formula S = n(n+1)(2n+1)  6 Find the sum of the squares of all the counting numbers between 15 and 35. … 
SUMS?
what is the sum of the first towo odd numbers? 
sum fun (math)
find a quick and easy method to compute the sum of the first 100 counting numbers (no calculators allowed) 
Math 8th grade
I NEED THESE IN ALGEBRAIC EXPRESSION!! The larger of two sums is 12 more than the smaller. Their sum is 84.Find the numbers. The sum of two numbers is 45. The first is 9 less than the second.Find the numbers. The second of two numbers … 
math
The sum of the first 5 natural numbers is 15 or (5)(6)/2. The sum of the first 21 natural numbers is 231=(21)(22)/2, and the sum of the first 30 numbers is 465. Use inductive reasoning to derive the formula for the sum of the first … 
math URGENT!!!!
i have a list of 5 different numbers. the sum of 2 of the numbers is 0. the sum of 2 of the numbers is 1. the sum of 2 of the numbers is 2. the sum of 2 of the numbers is 3. the sum of 2 of the numbers is 4.the sum of 2 of the numbers … 
Counting and Probability
What is the difference between the sum of the first 400 even counting numbers and the sum of the first 400 odd counting numbers? 
math
If two dice are rolled and their faces noted, find each of the following probabilities: a) the sum of the two dice is 8 b) both dice show even numbers c) the sum of the two dice is 8 OR both dice show even numbers d) the sum of the …