81 x 9 = 801. What must you do to make the this equation true?

I know a country, If you remove the last alphabet of its name, it will become a part of your body. Do you name it?

You can hear me, but you can't touch or see me.

What am I?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

I am an eight letter word and I am a computer terminology.
The second, third and fourth letters make an animal.
The fourth, fifth, sixth, seventh and eighth letters make a weapon.
The first, second, third and fourth letters can be taken as an outcome of any exam.
The fifth, sixth, seventh and eighth letter combine to form a high end typing software.

Can you tell who am I ?

John is 45 years older than his son Jacob. If you find similarities between their ages, both of their ages contain prime numbers as the digits. Also, John's age is the reverse of Jacob's age.

Can you find their ages?

Your mother’s brother’s only brother-in-law is asleep on your couch. Who is asleep on your couch?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

Complete the following series. It.s very logical:

1, 4, 5, 6, 7, 9, 11, __?

In this image, you can see three almost identical Doraemon images. Can you spot the odd one out from them?