GAM Box With Prisms For Brown Stair

The box contains 19 wooden prisms, each measuring 1x1x20 cm, in a natural wood finish. They are used to compare and calculate the volume of the prisms that make up the Brown Stair. The uniform 1x1x20 cm bars act as a measuring unit for that sensorial material.

The Brown Stair shows a child differences in two dimensions through its graded prisms. These montessori educational materials add a mathematical layer: by lining the 1x1x20 cm bars against each Brown Stair prism, the child can measure and calculate its volume. This turns a sensorial impression of size into a countable, mathematical result.

Each of the 19 prisms measures 1x1x20 cm and is finished in natural wood. Because every bar is the same size, the set works as a consistent unit for comparison, so the child can lay bars end to end or side by side to measure the larger Brown Stair prisms.

The box holds 19 identical 1x1x20 cm prisms, enough for a child to build up and measure against the different Brown Stair pieces and to compare volumes across the material. Having a set number lets the child check their calculations by counting how many unit bars fill a given prism.

This is an extension activity that moves from sensorial exploration toward measurement and calculation, so it suits children who already know the Brown Stair and are ready to work with volume. It typically appears in the later preschool or early primary years when a child begins to quantify what they first met through the senses.

Wipe the prisms with a soft, barely damp cloth and dry them before returning all 19 to the box. Store them out of direct sun and away from damp so the natural wood keeps its shape and the bars stay a true 1x1x20 cm for accurate measuring.