BRAIN TEASERS

enter your answer and press button OK

MATH PUZZLE: Can you replace...

MATH PUZZLE: Can you replace the question mark with a number?

Correct answers: 140

The first user who solved this task is Nasrin 24 T.

#brainteasers #math #riddles

Register with your Google Account and start collecting points.

Check your ranking on list.

I haven't spoken to my wife f...

I haven't spoken to my wife for 18 months. I don't like to interrupt her.

Jokes of the day - Daily updated jokes. New jokes every day.

Follow Brain Teasers on social networks

Brain Teasers

puzzles, riddles, mathematical problems, mastermind, cinemania...

Gas mask

In 1850, the first U.S. patent No. 7,476 for a gas mask with a self-contained breathing apparatus was issued to Benjamin J. Lane of Cambridge, Mass. for a "respiring apparatus." (The first U.S. patent for an "inhaler or lung protector" resembling a gas mask of the modern type was awarded to Lewis Phectic Haslett of Louisville, Ky., on 12 Jun 1849. It had a filter of woolen fabric or other porous substance to purify the air and remove dust.)

This site uses cookies to store information on your computer. Some are essential to help the site properly. Others give us insight into how the site is used and help us to optimize the user experience. See our privacy policy.