SOLUTION: What is the sum of the first 500 counting numbers? i.e. The sum of 1+2+3+4+...496+497+498+499+500? How about only the odds: 1+3+5+7+...493+495+497+499?

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Question 342323: What is the sum of the first 500 counting numbers? i.e. The sum of 1+2+3+4+...496+497+498+499+500? How about only the odds: 1+3+5+7+...493+495+497+499?
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
What is the sum of the first 500 counting numbers? i.e. The sum of 1+2+3+4+...496+497+498+499+500?
That's 500 numbers.
Put them in pairs:
1 & 500
2 & 499
3 & 498 etc
There are 250 pairs, each pair = 501
250*501 = 125250
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How about only the odds: 1+3+5+7+...493+495+497+499?
That's 250 numbers.
Pair them up like above.