In a lively show, mathematician and magician Arthur Benjamin races a team of calculators to figure out 3-digit squares, solves another massive mental equation and guesses a few birthdays. How does he do it? He’ll tell you. (15:14)

Learn mental math multiplication tricks Learn to multiply large numbers in your head. Uses benchmark numbers. Suggests practicing mental math to get better at it. Captions appear on the screen. (2:46)

Please make your comments on categories positive, and not just negative.

People work hard on educational categories, and we want to encourage them to make more!

Profanity (curse words), sexually suggestive remarks, and other such obviously inappropriate comments
will be deleted immediately, and are grounds for immediate expulsion. Remember, children use this website.

Personal criticism on project forums and in video content is not allowed and will be deleted immediately.
Any violations of this rule could result in expulsion from the project so please, no insults or other negative
personal remarks.

Very harshly-worded criticism of content will also be deleted promptly. Please use your vote to express your
harshest feelings. Repeated violations of this rule can result in expulsion. If you must criticize another
person's hard work, then be nice about it.

People work hard on educational categories, and we want to encourage them to make more!