# Featured

## Coordinate Grid Pictures, Slope, Distance, and Square Root Estimates and Sir Isaac Newton

I shared a story about Isaac Newton about what can happen during a shutdown. In 1665, Cambridge University closed as the bubonic plague swept across England. Isaac Newton, a 22-year-old student, was forced to retreat to the family farm, Woolsthorpe Manor. Isolated there for more than a year, on his own he revolutionized the scientific and mathematical world.

## Coordinate Grid Location: Descartes, Random Monsters, Shapes, and Pictures in 1 and 4 Quadrants

After learning the wonders of chess and recording games with algebraic notation, the natural progression was to explore the origins of coordinate grid location. The coordinate grid of an horizontal x-axis and vertical y-axis in two dimensions was proposed by the French mathematician René Descartes (1596 - 1650). (Pronounced "day CART").

## Chess Algebraic Notation, Combinations, Openings, Mate in One Puzzles

So with 32 pieces and 64 squares, how many different combinations of games can be played on a chess board?

## Magic of Nines with Digital Roots

Remember, that the **digital root** of a number is the number obtained by adding all the digits, then adding the digits of that sum, and then continuing until a single-digit number is reached. Zero can never be a digital root only 1,2,3,4,5,6,7,8 and 9.