Examples from some area tasks indicate that misconceptions about linear measurement can be carried over to area measurement; children will occasionally count points rather than length units or area units. (MP)

When primary children were interviewed to determine their perceptions of embedded triangles, they failed to observe overlapping triangles. Possible explanations for this and other response patterns are discussed, and implications for schooling are explored. (SD)

Discusses the use of middle-school students' natural understanding of large numbers to introduce the concept of infinity. Presents activities that investigate infinite sets by demonstrating a one-to-one correspondence between the counting numbers and the given set. Examples include prime numbers, Fibonacci numbers, fractions, even and odd numbers,…