How to explain volume of step-prisms in section a: volume of step-prisms to your student
27 October 2026
Understanding the volume of step-prisms is easier when you break the shape into smaller cuboids. This method helps children see how each part adds up to make the whole shape.
Example question
A step-prism is made of two cuboids. The bottom cuboid is 5 cm long, 4 cm wide, and 3 cm high. The top cuboid is 3 cm long, 4 cm wide, and 2 cm high. What is the total volume?
Step 1: Find the volume of the bottom cuboid. 5 × 4 × 3 = 60 cm³
Step 2: Find the volume of the top cuboid. 3 × 4 × 2 = 24 cm³
Step 3: Add the two volumes together. 60 + 24 = 84 cm³
The total volume of the step-prism is 84 cubic centimetres.
Key insight: By splitting a step-prism into separate cuboids, your child can work out the volume of each part and then add them together. Now your child will spot this method in similar questions and feel ready to practise more step-prism volume problems.
