1+2+3+4+…… +The sum of 2010 + 2011 is () A. odd B. even 1+2+3+4+…… +The sum of 2010 + 2011 is () A. odd B. even C. multiple

1+2+3+4+…… +The sum of 2010 + 2011 is () A. odd B. even 1+2+3+4+…… +The sum of 2010 + 2011 is () A. odd B. even C. multiple

1+2+3+4+…… +There are 2011 items in 2010 + 2011, which are odd. The first and last items are odd, so the sum is even

Is the sum of 1 + 2 + 3... + 2010 odd or even?

（1+2010）×2010÷2=2021055
Odd number
It can also be understood in this way that 1 + 2 is regarded as 1 pair, 3 + 4 as 1 pair, that is, 1005 pairs of odd numbers are added or odd numbers are added

The first question: is the sum of 99 odd numbers odd or even? The second question: is the sum of 2010 odd numbers odd or even?
I'll hand in my homework tomorrow! If all the answers are correct, I'll give you a lot of points!

The sum of 99 odd numbers is odd. The sum of 2010 odd numbers is even