The Secrets of Mental Math

The fundamental strategies of mental arithmetic; the value of adding from left to right, unlike what one does on paper; discovering how a variety of shortcuts hold the keys to rapidly solving basic multiplication problems; finding squares.

Professor Benjamin demonstrates how easily one can mentally add and subtract one, two, and three-digit numbers; shortcuts using the complement of a number; the uses of mental addition and subtraction for quickly counting calories and making change.

The secrets of easy mental multiplication; mastering how to quickly multiply any two-digit or three-digit number by a one-digit number; learning the most fundamental operations of mental multiplication; a vital tool to one's mental math tool kit.

A fundamental operation of arithmetic, division; exploring shortcuts for dividing by one and two-digit numbers; how to convert fractions such as 1/7 and 3/16 into decimals; determining when a large number is divisible by numbers such as 3, 7, and 11.

Real-world situations such as figuring out sales tax or how much to tip; one does not need an exact answer but just a fair approximation; developing skills for effectively estimating addition, subtraction, multiplication, division and square roots.

Sometimes one encounters math problems on paper in their daily lives; there are some rarely taught techniques to help speed up one's calculations; checking answers when one is adding tall columns of numbers and multiplying numbers of any length.

Benjamin shows five methods for multiplying any two-digit numbers; the squaring method, when both numbers are equal; the close together method, when both numbers are near each other; the subtraction method when one number ends in 6, 7, 8 or 9.

Solving basic math problems in your head offers lifelong benefits, including a competitive edge at work, a more active and sharper mind, and improved standardized test scores.

Memorizing long numbers may sound impossible; probing an effective way to memorize numbers using a phonetic code in which every digit is given a consonant sound; practicing by trying to memorize the first 24 digits of pi and credit card numbers.

Determining the day of the week of any date in the past or the future; knowing what day of the week was July 4, 2000, or Feb. 12, 1809; one will be surprised at how easy it is to grasp the simple mathematics behind this handy skill.

Professor Benjamin shows how to do squaring three-digit and four-digit numbers; cubing two-digit numbers; multiplying two-digit and three-digit numbers; knowing how to mentally solve these problems cements one's knowledge of basic mental math skills.

Professor Benjamin concludes by showing how to use different methods to solve the same problem; how to find the cube root of large perfect cubes; how to use the techniques one has learned and mastered thus far.