Remove two matchsticks to make the below equation correct.

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 is the end of everything?

What is the next number in the series?

15 29 56 108 208 ?

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.

The doctor advised his patient to take a tablet after every fifteen minutes. He gave him five tablets in total.

How much time will he take to have all the five tablets?

What has many keys but can’t open a single lock?

Replace the question mark in the picture below.

Can you count the number of squares in the figure below?

Can you make four (4) nines (9) equal 100?