Today I struggle with Math Competition. For sure I am flattered for getting this opportunity.

Few number of the questions in this Junior High School Math Competition, I try to figure it out as below :

1. 1 + 2 + … + 99 + 100 + 99 + … + 2 + 1 = …
   How to do this with fast way???
   Just take the middle number and multiply the same number too.
   100 x 100 = 10.000.
   
2. (1 – ½ ) ( 1 – ⅓ ) … ( 1 – 1 / 2012 )
   How to do this with fast way???
   Just take the last number : 1 / 2012.
   
3. 745² – 255² = …
   How to do this with fast way???
   ( 745 + 255 ) ( 745 – 255 ) = 490.000.
   

Another questions not in this Junior High School Math Competition that I found the simplest way to solve :

1. 1 + 2 + … + 118 + 119 = …
   How to do this with fast way???
   { ( 1 + 119 ) ( 119 : 2 ) } = 120 x 59,5 = 7140.
   
2. 1 + 2 + … + 179 + 180 = …
   How to do this with fast way???
   ( 180 + 1 ) ( 180 : 2 )
   181 x 90 = 16.290.
   
3. 11 + 22 + 33 + … =…
   10 + 20 + 30 + …
   How to do this with fast way???
   Just take the first number : 11 / 10.
   

That’s all I can do for you and hope all of you like my short way to solve the above questions.

Feel free to comment at my post.