If you want to sum up numbers 1 to N, you can do it this way. Sum = (N+1)*(N/2).
The reason this works: say you want to sum up 1 through 10. You have 10+1, 9+2, ..., 6+5. Each of these equals 11 [N+1]. You added 11 five times (N/2). Sum of 1 to 102 = (102+1)*(102/2) = 103*51 = 5253. You can check it by summing up the numbers with a spreadsheet.
The sum of the first 500 odd counting numbers is 250,000.
The sum of the first 50 counting numbers, excluding zero, is 1,251.
The sum of the first 10 counting numbers (1-10) is 51.
It is 155 greater.
The sum of the first 500 counting numbers (1-500) is 125,001.
The sum of the first 500 odd counting numbers is 250,000.
The sum of the first 50 counting numbers, excluding zero, is 1,251.
The sum of the first six counting numbers (1-6) is 19.
The sum of the first 10 counting numbers (1-10) is 51.
It is 155 greater.
The sum of the first 100 counting numbers (1-100) is 5,001.
The sum of the first 500 counting numbers (1-500) is 125,001.
4990
thousands
210
The sum of the first 500 even numbers, excluding zero, is 250,500.
1+1+1+1+1+=5 * * * * * The question did not ask for the sum of the first counting number five times! The sum of the first 5 counting numbers is 1+2+3+4+5 = 15. Such sums are known as triangular numbers.