I AM A BOX OBJECT USED TO WRITE LETTERS AND NUMBERS WHO AM RIDDLES WITH ANSWERS TO SOLVE - PUZZLES & BRAIN TEASERS

The quick brown fox jumps over the lazy dog. Did you answer this riddle correctly?
YES  NO  

An Elevator Did you answer this riddle correctly?
YES  NO  

Startling - starting - staring - string - sting - sing - sin - in - I. Did you answer this riddle correctly?
YES  NO  

Alone.

Behead me and I am Lone.
Behead me again and I am One. Did you answer this riddle correctly?
YES  NO  

Sugar Did you answer this riddle correctly?
YES  NO  

What has 4 letters.

Sometimes has 9 letters.

Never has 5 letters. Did you answer this riddle correctly?
YES  NO  

A cereal killer. Did you answer this riddle correctly?
YES  NO  

Post Office Did you answer this riddle correctly?
YES  NO  

The number missing on the left is 8 and the one on right is 7.

Explanation:
The pattern:
The number in the center of triangle is the square root of the sum of the numbers sitting outside on the corners.

Thus,
10 + 22 + 4 = 36
Square Root of 36 = 6

In the same manner:

10 + 42 + 12 = 64
Square Root of 64 = 8

12 + 22 + 15 = 49
Square Root of 49 = 7 Did you answer this riddle correctly?
YES  NO  

Only one, it's no longer empty after the first Did you answer this riddle correctly?
YES  NO  

The correct answer is T-H-A-T. Did you answer this riddle correctly?
YES  NO  

83. Did you answer this riddle correctly?
YES  NO  

The cabin was on a ship! Did you answer this riddle correctly?
YES  NO  

All numbers(0-9) appears in alphabetical order and once. Did you answer this riddle correctly?
YES  NO  

The letter C. (Sea) Did you answer this riddle correctly?
YES  NO