what does the below math rebus puzzle mean?

A girl was sitting in her hotel room when she heard a knock on the door. She opened the door and found that a man was standing outside.
The man said, "Oh! I am really sorry, I thought this was my room."
He then walked through the corridor to the elevator. The girl did not know the man. She closed her door and called security asking them to apprehend the man.
What made her suspicious of that man? He might have been genuinely mistaken.

What is full of holes but still holds water?

You are provided with a grid (as shown in the picture). Can you fill the squares with numbers 1-8 in a manner that none of the two consecutive numbers are placed next to each other in any direction (vertically, horizontally or diagonally?)

Why is the Hole below a Lock?

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?

A sundial has the fewest moving parts of any timepiece. Which has the most?

What three numbers, none of which is zero, give the same result whether they’re added or multiplied?

In a concert, Christina is performing a dance show with her group.
At 10:00, she and her crew were dancing in an absolutely straight line. At that time Christina was standing in 4th position from both the front and back end of the row.

What was the size of her crew?

Can you spot the hidden girl in the picture below?