Formula 1-2 + 3-4 + 5-6 + +Is the result of 1999-2000 + 2001-2002 odd or even

First of all, add odd number 1 + 3 + 5 + 7 +. 2001, then add even number, add odd number sum minus even number sum is the result, the result is calculated as follows: there are 1001 even numbers, even number sum is: n * (n + 1) = 1001 * 1002 = 1003002, sum: (1 + 2002) * 2002 / 2 = 2005003, sum minus even number sum = 2005003-1003002 = 1002001, so it is odd number!

RELATED INFORMATIONS

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