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what is all the numbers from 1 to 100 added up?

math arithmetic
 Aug 22, 2014

Best Answer 

 #2
avatar+111470 
+10

There is a "formula" for this. But notice when we add the first number, 1, and the last number, 100, we get 101. And addnig the next-to-the-last number, 99, and the second number, 2, we also get 101. And, continuing in this manner, we have 50 pairs of numbers that each add to 101. Therefore, 50 * 101 = 5050.

 

 Aug 22, 2014
 #1
avatar+111246 
+10

You can think of it like this

0,    1,   2,  ......................49

100,99,98,........................51

--------------------------------add

100+100+100..................100 ,    The only missing number is 50

So answer must be 100*50+50=5050

 Aug 22, 2014
 #2
avatar+111470 
+10
Best Answer

There is a "formula" for this. But notice when we add the first number, 1, and the last number, 100, we get 101. And addnig the next-to-the-last number, 99, and the second number, 2, we also get 101. And, continuing in this manner, we have 50 pairs of numbers that each add to 101. Therefore, 50 * 101 = 5050.

 

CPhill Aug 22, 2014
 #3
avatar+111470 
0

Ah...Melody beat me to it.....rats!!!!!!

 

 Aug 22, 2014
 #4
avatar+111246 
0

Never mind Chris I gave you points anyway lol

I am quite enjoying the two of us answering questions with different approaches.

It opens up horizons. 

 Aug 22, 2014

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