- #1

- 47

- 0

Can you count and add all the numbers 1-100 without using a calculator?

- Thread starter konartist
- Start date

- #1

- 47

- 0

Can you count and add all the numbers 1-100 without using a calculator?

- #2

- 360

- 0

You got me!konartist said:Can you count and add all the numbers 1-100 without using a calculator?

- #3

VietDao29

Homework Helper

- 1,423

- 2

As a metter of fact, I think I can

If I am not mistaken then Gauss did it centuries ago...

If I am not mistaken then Gauss did it centuries ago...

- #4

- 664

- 3

Let's hope not! ... Maybe all the *integers*, tho :)konartist said:Can you count and add all the numbers 1-100 without using a calculator?

(And yeah, you can use the old ((S+F)/2)*(F-S+1) trick to add all the integers between S and F)

DaveE

- #5

- 918

- 16

Well it wasn't easy, but there are 100 of them.konartist said:Can you count and add all the numbers 1-100 without using a calculator?

- #6

- 47

- 0

Yes sir, an old wive's tale is that he one day was punished in 3rd grade class and the teacher asked him to add all the numbers 1-100 thinking it would keep him busy, but he was able to reply the answer back to her in a matter of seconds.VietDao29 said:As a metter of fact, I think I can

If I am not mistaken then Gauss did it centuries ago...

- #7

- 124

- 0

yea u just use the formula...sum = 0.5n(n+1)

so 0.5 x 100 x 101 =50 x 101 = 5050

so 0.5 x 100 x 101 =50 x 101 = 5050

- #8

AKG

Science Advisor

Homework Helper

- 2,565

- 4

- #9

- 32

- 0

So what you're all saying is, find the average value (50.5) and mutiply by the number of terms.

- #10

- 1,085

- 6

What is 50.5 the average value of?Cybersteve said:So what you're all saying is, find the average value (50.5) and mutiply by the number of terms.

- #11

VietDao29

Homework Helper

- 1,423

- 2

I think he meant the average value of the first term and the last term, ie:mattmns said:What is 50.5 the average value of?

(1 + 100) / 2 = 50.5

- #12

- 32

- 0

50.5 is the average value of all the numbers 1 to 100 inclusive.mattmns said:What is 50.5 the average value of?

If there were an odd number of terms in an evenly spaced sequence the average would be the middle term.

As this sequence is even the average value is the average of the two middle terms - 50 & 51.

- #13

- 1,085

- 6

Ahh, I must have misread something.

- #14

- 918

- 16

Not so much misread as partially read. 50.5 is not only the average of 1 and 100. It is also the average of 2 and 99, 3 and 98, etc. That is, it is the average of the set of integers from 1 to 100.mattmns said:Ahh, I must have misread something.

- #15

- 27

- 0

im lost....

- #16

- 1,984

- 3

This is easy.

Here is a lecture that shows you how to do it.

http://www.jimloy.com/algebra/gauss.htm [Broken]

Here is a lecture that shows you how to do it.

http://www.jimloy.com/algebra/gauss.htm [Broken]

Last edited by a moderator:

- Last Post

- Replies
- 9

- Views
- 3K

- Replies
- 10

- Views
- 2K

- Replies
- 29

- Views
- 72K

- Last Post

- Replies
- 53

- Views
- 46K

- Last Post

- Replies
- 20

- Views
- 3K

- Replies
- 4

- Views
- 8K

- Last Post

- Replies
- 6

- Views
- 1K

- Last Post

- Replies
- 1

- Views
- 1K

- Last Post

- Replies
- 16

- Views
- 3K

- Last Post

- Replies
- 24

- Views
- 12K