9 and 10 years old

Nine and ten-year-olds are using math to do stuff. They’ll design a brand new pattern the world has never seen, and then devise a scheme to beat you at cards.
A rectangle made of 12 teal-colored kites, four pink right triangles, and four blue diamonds in an arrangement that has both horizontal and vertical lines of symmetry.
A 21st Century Challenge

A 21st Century Challenge

After seeing Hana Murray's lovely study of rectangles made from 21st Century Pattern Blocks, I started playing and noticed that many of them seemed to involve the small green triangles. Pretty soon, I had formed a conjecture. Using copies of these at least two...

Reading the weather page

Reading the weather page

An important part of training young minds is modeling a healthy skepticism. Today's weather column in the Star Tribune included the following observation: Minnesota is nippy during the winter...but we don't have to stress about tsunamis, volcanoes or...

Cookies under constraints

Cookies under constraints

A propos of nothing one day, I ask Griffin (9 years old at the time, finishing up fourth grade) a question. Me: Griff, imagine you are baking cookies and you need $latex \frac{3}{4}$ cup of sugar, but you only have a $latex \frac{1}{2}$ cup measure. How would...