Ep 2. Mental Addition and Subtraction

In the second episode of season one of Secrets of Mental Math, titled "Mental Addition and Subtraction," viewers will delve deeper into the world of mental calculation and learn strategies for quickly adding and subtracting large numbers in their heads. Host Arthur Benjamin, a renowned mathemagician, will guide viewers through several examples and explain the underlying principles that make mental math possible.

The episode begins with Benjamin revisiting some of the basic techniques covered in the first episode, such as breaking numbers down into easier to manage units and using simple arithmetic shortcuts like doubling and halving. He then introduces several new strategies for mental addition and subtraction, including using number bonds and making use of complementary numbers.

One powerful mental math technique that viewers will learn in this episode is called the "complement method." This method involves subtracting a number from its complement, which is the amount needed to reach the nearest multiple of 10, 100, or other significant number. For example, to mentally add 7 + 8, a viewer could recognize that 7 and 3 (its complement for 10) add up to 10, and that 8 and 2 (its complement for 10) add up to 10 as well. Therefore, 7 + 8 can be mentally calculated by first adding 10 + 10 (which equals 20) and then subtracting 2, for a total of 16.

Another strategy that viewers will learn in this episode is to use number bonds, which are simply the ways in which numbers can be broken down into their constituent parts. For example, the number 9 can be thought of as a bond between 5 and 4, or between 8 and 1. By recognizing number bonds, viewers can quickly add and subtract numbers that would otherwise require tedious mental effort.

Throughout the episode, Benjamin provides plenty of opportunity for viewers to practice these mental math techniques, using everything from simple addition and subtraction problems to more complex calculations involving three-digit numbers. Along the way, he explains the reasoning behind each strategy, helping viewers to truly understand how mental calculation works and why it can be so effective.

One particularly noteworthy moment in the episode occurs when Benjamin demonstrates how the complement method can be extended to larger numbers by breaking numbers down into parts and considering complements for each part. For example, to add 49 + 37 mentally, a viewer could recognize that 49 is just one less than 50 (which has a complement of 50) and that 37 is 3 less than 40 (which has a complement of 60). Therefore, the problem can be mentally solved by adding 50 + 60 (which equals 110) and then subtracting 4 and 3 (for a total of 7), resulting in an answer of 82.

By the end of the episode, viewers will have a solid foundation in mental addition and subtraction, as well as a newfound appreciation for the power of mental math. They may even find themselves looking for opportunities to test their skills in everyday life, from figuring out a tip at a restaurant to mentally calculating the square footage of a room.

In "Mental Addition and Subtraction," the second episode of Secrets of Mental Math season one, viewers of all ages and math skill levels will learn practical and effective strategies for performing mental calculations quickly and accurately. Through engaging examples and clear explanations, Arthur Benjamin will help viewers to unlock the mysteries of mental math and develop a valuable new skill.