What building has the most stories?

Our product and our sum always give the same answer. Who are we?

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

Count the number of lines in the image below ?

If six children and two dogs were under an umbrella, how come none of them got wet?

I have four wings but can't fly.
I express no emotions.
I am found on the exact spot every time you look.
I keep toiling away with a little sound.

Do you know what am I?

Spot what is wrong here in below Picture?

A mathematician couple was having a Frappuccino in Starbucks sitting opposite to each other. Suddenly the guy noticed the text written on the paper in front of them and exclaimed that it was wrong. The girl denied it and said it is appropriate. Both are correct. What is written on the paper?

Which wheel of car does not rotate when you turn your car right?