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 ...

“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 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.

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 ...