The sum of the first "n" numbers is equal to n(n+1)/2.
The sum of all the numbers 1 through 200 is 20,100.
The sum of all odd numbers 1 through 99 is 9,801.
The sum of all the numbers from 101 through 200 is 15,050.
You can calculate the sum of numbers by adding numbers together. You can calculate the product of numbers by multiplying those numbers.
500
The sum of all the odd numbers from 1 through 100 is 10,000
100
If the question is asking for the sum of natural numbers between two members of N, then you will have to add all the natural numbers between the two numbers (excluding the actual two numbers). For example, if they ask you to calculate the sum between 2 and 5, your answer should be 3+4=7.
You use the formulae (n^2 + n)/2 So as n = 200 that would be 20,100
The sum of all even numbers from 2 through 200 is 40,200.
The sum of all prime between numbers 1 and 400 (2 through 399) is 13,887.
The sum of the numbers from 1 through 100 is 5,050.