What does the below image rebus riddle means ?

Replace the question mark with the correct number below.

There are seven sisters in a house in a village where there is no electricity or any gadget.

Sister-1: Reading Novel
Sister-2: Cooking
Sister-3: Playing Chess
Sister-4: Playing Sudoku
Sister-5: Washing clothes
Sister-6: Gardening

what is Sister-7 doing ?

what does this picture(rebus) riddle means ?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

Prove that the below maths equation is true.

8 + 8 = 91

The captain of a ship is telling you an interesting story and then poses a question. He says, “I have travelled the oceans far and wide. One time, two of my sailors were standing on opposite sides of the ship. One was looking west and the other one east. And at the same time, they could see each other clearly. Can you tell me how that was possible?”

I am Huge on Sunday and Saturday.
I am small from Tuesday to Thursday.
I do not exist on Monday and Friday.
Who am I?

Can you Find and name the hidden bird in the picture below ?