What is the sum of all the numbers from 1-1000?

Answer 1

1001

Answer 2

Let's look at some patterns:

1 + 1000 = 1001

2 + 999 = 1001

3 + 998 = 1001

4 + 997 = 1001

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So there are 500 pairs of numbers that have a sum of 1001.

Thus, the sum of numbers from 1 to 1000 is 500*1001 = 500,500.