0
20*(20+1)/2 = 210
If you want to see how this works, or even the beauty in numbers, you can do so in MS Excel. In cell A1 put "=ROW()" B1: "=SUM(A$1:A1)" C1: "B1/A1". Then, select and copy those three cells. Paste the content in any number of rows down in those three columns.
Be sure to note the following patterns:
Every 20 numbers, the one's digit repeats itself in the sum column (B column),
The sum of the first 10 numbers is 55, the first 100 is 5050, 1000 is 500500.
What else can I help you with?
What is the sum of the first 50 counting numbers?
The sum of the first 50 counting numbers, excluding zero, is 1,251.
What is the sum of the first 500 odd counting numbers?
The sum of the first 500 odd counting numbers is 250,000.
What is the sum of the first six counting numbers?
The sum of the first six counting numbers (1-6) is 19.
What is the sum of first 10 counting numbers?
The sum of the first 10 counting numbers (1-10) is 51.
How much greater is the sum of the first 20 counting numbers than the sum of the first 10 counting numbers?
It is 155 greater.
What is the sum the first 100 counting number?
The sum of the first 100 counting numbers (1-100) is 5,001.
What is the sum of the first 500 couting numbers?
The sum of the first 500 counting numbers (1-500) is 125,001.
What is the sum of the first 100 counting numbers?
4990
The sum of the the first ten counting numbers?
thousands
Give the sum of the first 20 counting numbers?
210
What is the sum of the first five hundred even numbers not counting zero?
The sum of the first 500 even numbers, excluding zero, is 250,500.
What is the sum of the first 5 counting numbers?
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.
