If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

What 5-letter word typed in all capital letters can be read the same upside down?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

The following four words might seem abrupt to you. But you can make them meaningful by just adding vowels.
RDSH
GGPLNT
TMT
NN

Hint: All of them are vegetables.

Which flower has two lips?

You have a 12 liters jug full of water. You have two empty 8 liters and 5 liters jug. How can you divide the water into two equal parts using these jugs?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?

What goes up but never comes down?

A girl says this to her best friend: “I was born in 1955, and I celebrated my 17th birthday last weekend.” Her best friend thinks she’s lying, but she’s actually correct. How is that possible?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?