The note
How schools teach it now
Children count cubes first, then use length × width × height in cm³ or m³. Surface area (adding the areas of all six faces) is mostly secondary work but appears in some 11+ papers.
5-minute kitchen-table activity
Measure a cereal box or shoe box. Guess how many 1 cm cubes (about the size of a sugar cube) would fill it, then work out length × width × height. How close was the guess?
Worked example
A box is 6 cm long, 4 cm wide and 5 cm high. What is its volume?
- One layer on the bottom: 6 × 4 = 24 cubes.
- There are 5 layers: 24 × 5 = 120.
Answer: 120 cm³
Common mistakes to watch for
- Adding the lengths instead of multiplying them.
- Writing cm² instead of cm³.
- Forgetting the hidden cubes at the back of a stack.
Encouragement
- Try saying
- “How many cubes in one layer? How many layers?”
- Rather than
- “Just times all the numbers.”