“Lettuce Grows Into a Processed Food” [Aug. 19] compares commodity lettuce with ready--to-eat packaged salads and in so doing may have created the wrong impression. The article equates the “shape” of ...

In pre-kindergarten, children ages 3-5 develop a basic understanding of numbers and counting, and connect both to the idea of “how many.” Pre-k math tips work on recognizing, grouping, and comparing ...

In nature, many things have evolved that differ in size, color and, above all, in shape. While the color or size of an object can be easily described, the description of a shape is more complicated.

In nature, many things have evolved that differ in size, color and, above all, in shape. While the color or size of an object can be easily described, the description of a shape is more complicated.

A hierarchic clustering, or tree, of several objects can be described by an object x object matrix, whose elements are the number of nodes of the tree lying on the path connecting a pair of objects.

Take on this spot-the-difference challenge. Within 36 seconds, identify three differences in teeth cleaning images by comparing shapes, colours, and textures. It’s like a pirate treasure hunt—victory ...