What country can make you shiver?

What is a word made up of 4 letters, yet is also made up of 3. Sometimes is written with 9 letters, and then with 4. Rarely consists of 6, and never is written with 5.

There is a place where if I stand up straight, I will still be considered sideways.

There once were seven dwarfs who were all brothers. They were all born two years apart. The youngest dwarf is seven years old. How old is his oldest brother?

What has a bottom at the top?

I have a five and a three-gallon jar. Assuming there is an infinite supply of water, how can I measure one-gallon water?

My grandson is about as many days as my son in weeks, and my grandson is as many months as I am in years. My grandson, my son and I together are 120 years. Can you tell me my age in years ?

There was a strange boy who was born before his father. How can this be possible?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?