Step by step
The question
Question: draw the net of a cube, side 5, and find its surface area.
The surface area is the area of all the outside faces together.
A net shows every face flat.
1 Unfold it
We cut along some edges and fold it flat.
Matching faces have the same colour.
2 Area of each face
Top and bottom: 5 × 5 is 25.
Front and back: 5 × 5 is 25.
The two sides: 5 × 5 is 25.
Careful!
Count every face in the net.
A box has 6 faces, not 3.
3 Add them all
We add all 6 faces: 150.
4 Check
Let's check another way.
All 6 faces of a cube are the same square: 6 times 25 is 150.
So the answer is right!
Let's look back.
First: unfold it.
Then: area of each face.
Then: add them all.
Last: check.