Measurement & Data

January 9, 2020

Measurement: Volume

Informally, volume is the amount of (three-dimensional) “stuff.” The volume of a body of water is how much water there is. The volume of a sculpture […]
December 3, 2019

The Number Line – subtraction, and measurement

The number line is not just a school object. It is as much a mathematical idea as functions. Unlike the Number Line Hotel, hundreds charts, Cuisenaire rods, and base ten blocks, the number line is not just a pedagogical aid used only to help children learn; mathematicians refer to it, too.
December 3, 2019


The word dimension is related to the word measure. It is used in two ways in geometry. It is used to specify a measurement: “What are […]
December 3, 2019

Shape: Circle

"Circle" is a familiar word to most children very early, but with little more than an informal sense of "round." We sit "in a circle" without much thinking about how round it is, and without picturing the geometrical object associated with the word.
November 21, 2019

Shape: Quadrilateral

A quadrilateral is a polygon that has exactly four sides. (This also means that a quadrilateral has exactly four vertices, and exactly four angles.)
November 21, 2019

Measurement: Discovering formulas for area

Area formulas Students who have the informal notion that area is the “amount of 2-D ‘stuff'” contained inside a region can invent for themselves most of […]
November 4, 2019

Measurement: Length, width, height, depth

Length, width, height, depth Outside of the mathematics class, context usually guides our choice of vocabulary: the length of a string, the width of a doorway, […]