M3.6.8 For the adult
Surface area
How much paper do I need to wrap this box?
What this chapter teaches
A cuboid has six rectangle faces in three matching pairs. The surface area is the total area of the six faces, which is the paper that covers the box with no gaps. Surface area is in cm², and volume is in cm³: they are different measures.
Three questions to ask
There is no one right wording. Listen for the idea.
- How many faces does a box have, and which of them are the same size?
- How would you find the paper needed to wrap a box 5 cm long, 3 cm wide and 2 cm high?
- Why is the surface area in cm² but the volume in cm³?
After the chapter, the learner can
- Find the surface area of a cuboid from its net
- Find how much paper covers a box with no gaps
What they copy into their notebook
A cuboid has 6 faces in 3 pairs. Surface area = 2 × (l × w + l × h + w × h). It is the paper that covers the box with no gaps, in cm². Volume is a different measure, in cm³.