# Featured

## One Grain of Rice (K and 1st Grade) Doubling with the first 30 powers of 2 -- Exponential Growth

Many years ago, there lived a selfish raja in India. He ruled that all the people should give him almost all of their rice for safekeeping so that in a time of need there would be rice to eat.

## The Story of Montarek (2-5th Grade) — Doubling, Tripling, Quadrupeling and Adding Five (Exponential Growth vs. Linear)

After a week focusing on exponential growth in the population of the world and most of its countries, I shared an ancient legend with the chlldren about The Story of Montarek, which better emphasizes the power of exponential growth. In the Montarek saga, a peasant girl saves the King’s daughter and is offered a reward.

## World Population from 10,000BC to 2100AD (number notation, years to next billion and doubling)

Tracking the world population has always been a fascination for me. I particularly enjoyed the billion benchmarks reached for 4, 5, 6, and 7 billion during years 1974, 1987, 1999, and 2011, respectively.

## Monty Hall Dilemma: What Is The Probability If You Stay or Switch?

40 years ago, in 1975, the television game show, *Let’s Make a Deal,* inspired a brain teaser posed in a letter to a magazine called the *American Statistician*. It became famous when it was again posted in 1990 in another magazine called *Parade* in a column called *Ask Marilyn*.

## Palindrome Created by Adding Reverse Numbers and Lychrel Numbers

A “palindrome” is a number that is the same even when reversed such as 121 or 99 or 14641 and even 5.