Which word does the below Plexor means ?

The following sentence is false. The preceding sentence is true.
Are these two sentences true or false?

If eleven plus two equals one, what does nine plus five equal?

If 1+9+8=1, what is 2+8+9?

There are nine dots in the picture that has been attached with this question. Can you join all the dots by drawing four straight lines without picking up your pen?

Jim and Sarah are in a long-distance relationship. Jim buys an engagement ring for Sarah and wants to mail it to her. Unfortunately, the only way to ensure the ring will be received is to place a lock on the package. Jim has locks and Sarah has locks, but neither has keys for each other’s locks. How can they make sure the ring isn’t stolen?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

John was drowned by he was not wet. How?

How many triangles can you count in the figure given?

I am a number I am not an odd number I am higher than 90 I am not higher than 100 If you subtract me from 100, you get nothing. What number am I?