SOLUTION: Find the sum of all of the 3-digit positive integers.

Question 1084522: Find the sum of all of the 3-digit positive integers.
Found 2 solutions by htmentor, Alan3354:
Answer by htmentor(1343) (Show Source): You can put this solution on YOUR website!
The three digit positive integers range from 100 to 999.
This is an arithmetic sequence with a common difference of 1.
The sum of n terms of an arithmetic sequence is S_n = (n/2)(a_1 + a_n)
The last term, 999, corresponds to n = 900.
Thus S_n = (900/2)(100+999) = 494550
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
Find the sum of all of the 3-digit positive integers.
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Sum from 100 to 999
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100 to 999 --> 900 numbers
Use 450 pairs.
100 + 999 = 1099
101 + 998 = 1099
etc
450*1099 = 494550
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