Random query expectation

#1

What is expectation telling here?Example: When l=1 and r=2 sir is calculating 1/21/22 . What does it mean?

#2

Hello @govilayush, here l = 1 and r = 2 for ex.
2
1 2
So we have two choices for l and we chose l as 1 so it’s probability as 1/2
and so we have two choices for r and we chose r as 2 so it’s probability as 1/2
And in this range from l = 1 to r = 2 we have two distinct nos. so 2 is getting multiplied.
So, overall it became 1/2*1/2*2.
I hope it is clear to you. In case if you face any issue or error pls let me know.