Haven't you studied this in 1st grade?

Algebra Level 3

Step 1: We define S= 1 -2+3-4...................

Step 2: See the photo above

Step 3: Adding the four Equations

Step 4: S = 1/4

That's nonsense, bu when I try to figure out where I was wrong I couldn't . Will you do that for me?

I will post the solutions tomorrow. Please visit to see that.