Stack a layer. See the volume.

SparkClass

Build a rectangular prism one real unit cube at a time.

CCSS 5.MD.C.4 · 5.MD.C.5a–b
Live Construction
24 / 24 cubes built
A rectangular prism built from unit cubes A 4 by 3 by 2 prism with 24 unit cubes in 2 layers.
01

2 layers, 24 unit cubes. Each layer has 4 × 3 = 12 cubes.

Current layer
Base Area · l × w12square units
×
Height · h2units
=
Volume24cubic units

Three ways to think like a builder

Don’t start with the formula. Start by noticing what one layer does.

1

Fill the base

Set the length and width. Drag the layer slider from 0 to 1. Why does one layer contain exactly l × w cubes?

2

Repeat the layer

Play the build. Every new layer adds the same number of cubes. The complete volume is (l × w) × h, also written l × w × h.

3

Look inside

Turn on Explode layers. Count the separated layers and check that no extra cubes appeared—only the spacing changed.

CCSS alignment: 5.MD.C.4 — measure volume by counting unit cubes. 5.MD.C.5a–b — connect volume to packing layers and use V = l × w × h and V = b × h.