Grade 5 maths · Volume of rectangular prisms

Building in Roblox: Understanding Volume

Stack unit cubes into rectangular prisms and discover why volume equals length × width × height — the same maths Roblox Studio uses to size every block.

Section 1 · Counting cubes

Volume is the space inside a structure

By the end of this section I can count unit cubes to measure volume — so I can plan how many blocks a Roblox build needs.

Success criteria 0 / 3 ticked

Tick each one when you can do it without help.

1A What is volume?

When you place a block in Roblox Studio, it fills a chunk of space. The amount of space inside a solid figure is its volume. We measure it by counting how many unit cubes fit inside with no gaps.

Key terms

volume unit cube cubic unit rectangular prism

A unit cube is a cube that is 1 unit long, 1 unit wide and 1 unit high — exactly 1 cubic unit of space. A rectangular prism is a box-shaped solid with six rectangular faces. Stack unit cubes into a prism and the total count is the volume.

Counting cubes in a small structure

A prism is 3 long, 2 wide and 2 high. picture it as stacked layers
One layer = 3 × 2 = 6 unit cubes count the flat base first
Two layers = 6 × 2 = 12 unit cubes stack the second layer on top
Volume = 12 cubic units

Interactive · build a box from unit cubes

3
2
2

Check yourself

A Roblox planter is 4 long, 3 wide and 2 high. How many unit cubes is that?

Find the cubes in one layer first by multiplying length by width.
One layer = 4 × 3 = 12 cubes. Two layers = 12 × 2 = 24. Volume = 24 cubic units.

A flat platform is 5 long, 5 wide and 1 high. What is its volume?

A height of 1 means the whole structure is just one layer.
One layer = 5 × 5 = 25 cubes, and there is 1 layer. Volume = 25 cubic units.

1B Counting cubes in layers

Instead of counting every cube one by one, count one layer and then multiply by the number of layers. Each layer of a rectangular prism has the same number of cubes.

Layer-by-layer counting

A prism is 4 long, 3 wide and 3 high. three identical layers
One layer = 4 × 3 = 12 cubes the flat base
3 layers = 12 × 3 = 36 cubes stack them up
Volume = 36 cubic units

Check yourself

A wall is 6 long, 1 wide and 3 high. How many unit cubes is that?

Each layer holds 6 × 1 cubes — find that first.
One layer = 6 × 1 = 6 cubes. 3 layers = 6 × 3 = 18. Volume = 18 cubic units.

A podium is 3 long, 2 wide and 5 high. What is its volume?

Work out the cubes in one layer, then multiply by the height.
One layer = 3 × 2 = 6 cubes. 5 layers = 6 × 5 = 30. Volume = 30 cubic units.

Section 2 · Length × Width × Height

Multiply to find volume fast

By the end of this section I can use the formula V = L × W × H — so I can size builds in Roblox Studio without counting every cube.

Success criteria 0 / 3 ticked

Tick each one when you can do it without help.

2A The volume formula

Counting layers always works, but multiplying is faster. The volume of a rectangular prism equals length times width times height.

The formula

V = L × W × H

L × W gives the cubes in one layer (the base area). Multiplying by H stacks that many layers. So V = L × W × H gives the total unit cubes in one step.

Using the formula

A storage crate is 5 long, 4 wide and 3 high. apply the formula
V = L × W × H
V = 5 × 4 × 3 = 60 multiply in any order
Volume = 60 cubic units

Interactive · see the formula come to life

4
3
5

Check yourself

Use the formula. A storage chest measures 6 × 4 × 3. What is its volume?

Multiply length by width first, then by height.
V = 6 × 4 × 3. First 6 × 4 = 24, then 24 × 3 = 72. Volume = 72 cubic units.

A swimming pool is 10 long, 5 wide and 2 high. Volume in unit cubes?

Multiply the three dimensions together in any order.
V = 10 × 5 × 2. 10 × 5 = 50, then 50 × 2 = 100. Volume = 100 cubic units.

2B Solving volume problems

Real builds come with words, not just numbers. Read the dimensions, choose the units, then apply the formula.

A word problem

A bookshelf block is 8 long, 3 wide and 5 high. Find its volume. identify L, W, H
V = L × W × H
V = 8 × 3 × 5 = 120 8 × 3 = 24, then × 5
Volume = 120 cubic units

Check yourself

A gift box is 7 long, 4 wide and 3 high. What is its volume?

Pick out the three numbers and multiply them together.
V = 7 × 4 × 3. 7 × 4 = 28, then 28 × 3 = 84. Volume = 84 cubic units.

A stage platform is 8 × 8 × 2. How many unit cubes is that?

A square base means length and width are the same number.
V = 8 × 8 × 2. 8 × 8 = 64, then 64 × 2 = 128. Volume = 128 cubic units.

This lesson took 60 seconds to make. Make one about YOUR kid's obsession, free.

Same Grade 5 Math outcomes, rebuilt around whatever your child is into this week - dinosaurs, Minecraft, horses, you name it.

Make your own lesson

This is a fixed example. Sprout writes a fresh, personalised lesson around your child every time - the example is the ad, the product is the personalisation.