1 + 1 + 1 + 1 + 1 + 1 + … = 1 + (-1) + 2 + (-2) + 3 + (-3) + 4 + (-4) + 5 + …
You forgot -5+6 on purpose.
spoiler
"In the expression on the right, all the terms cancel out"
You forgot the last one which is equal to the sum on the left.
1 + 1 + 1 + 1 + 1 + 1 + … = 1 + (-1) + 2 + (-2) + 3 + (-3) + 4 + (-4) + 5 + …
You forgot -5+6 on purpose.
spoiler
"In the expression on the right, all the terms cancel out"
You forgot the last one which is equal to the sum on the left.