# Featured

## Knight's Uncrossed Open and Polygons

In 1968, L. D. Yarbrough introduced a new variant on the classic problem of knight's tour. In addition to the rule that a knight touring a chessboard cannot visit the same cell twice, the knight is also not

The children showed up to class with an extreme level of enthusiasm. Many children solved Knight’s Tours (1-64), some solved very rare Closed Tours (64th move to 1st is a knight’s move).

## Knight’s Tours: Worlds Oldest Math Challenge

Over the last two weeks, we have studied the content of water and water used by the human body and by humans in the products that we manufacture.

## Water Crisis: How Mathematicians Save the Planet

Last week, we learned about the percentage content of water in our bodies and in the foods we consume. We also learned how much water we need to consume each day to stay hydrated and healthy. This week, we learned about how much water we have to sustain a healthy life.

## Water Content of Body and Food, How Much Water Should You Drink, Percents, Simplify Fractions

Up to 60% of the human adult body is water. The brain and heart are composed of 73% water, and the lungs are about 83% water. The skin contains 64% water, muscles and kidneys are 79%, and even the bones are watery: 31%.