Primary 4 · Mathematics
P4 nets
One check decides most of the marks here: not counting six squares, but folding the shape up in your head. Here is what the slip looks like, and how to catch it at home.
- Level
- P4
- Usually taught
- Term 4
- Covers
- 1 concept
What changes at P4
In Primary 4, a net is the flat shape you get by unfolding a solid, and your child learns to tell which flat shapes fold back up into a cube. It is the first real test of picturing a 3-D shape from a 2-D drawing.
The whole skill is one habit: fold it in your head. A cube has six faces, so a cube net has six squares, but six squares is not enough on its own. The squares have to be arranged so the shape actually closes up.
The sentence that costs the mark
A flat shape is made of six squares. Does it fold up into a cube?
What the working usually does
counts6 squares=a cube
Counts the faces, sees six, and stops. A cube has six faces, so the shape passes the count and the working looks done.
What the question asked
folds6 squares=not a cube
Folds the shape up in the mind. Two faces that should end up opposite are side by side, so they collide and the shape never closes.
Six squares is the right number, a cube does have six faces, so the count feels like proof. The only real test is folding it up: if two faces that should end up opposite sit side by side, they collide, and the shape never closes into a cube.
The same question, worked properly
Count the faces, but do not stop there
6 squares = maybe a cubeA cube has six faces, so six squares is needed. It is a start, not the answer.
Fold it up in your head
opposite faces never touchThis is the step that fails. On a real cube net, every face and its opposite are separated by another face. If two faces that must end up opposite are side by side, the shape cannot close. Skipping this fold and trusting the count is where the mark goes.
Check for a collision
two faces overlap = no cubeThe shape that folds with no overlap is the cube net. The one where two faces land on the same side is not, however tidy its six squares look.
How can you tell it has clicked?
Ask your child to point at two faces that will end up opposite each other, then check they are not touching in the flat shape. If they can find a separated pair for all three axes, they are folding it properly, rather than only counting the faces.
If they answer "six squares, so yes" without folding, that is where the mark goes. The count is the trap. The fix is to run the fold in their head, or with a real cut-out.
One thing to try tonight
Unfold an empty cereal or tissue box carefully along its edges. The flat shape it makes is its net. Fold it back and watch which flaps become opposite faces. They were never next to each other on the flat.
Then draw a few six-square shapes and guess together which fold into a cube, before cutting them out to check. The guessing, then testing, is exactly the skill the exam asks for.
What your child will meet in this topic
- Nets of Solids
Most Singapore schools introduce this in Term 4, though schools do differ by a term either way. If your child’s school runs a different order, you can set it in the schedule on your dashboard.
What it leads to
Reading a net is the groundwork for surface area and volume, where your child moves between a solid and its faces all the time. Picturing the fold is what makes those later topics feel concrete rather than abstract.
A child who folds shapes in their head here tends to find 3-D questions in P5 and P6 far less daunting, because they are seeing the solid, not just the drawing on the page.
More in Primary 4
Other topics in the same year, so you can see what sits either side of this one.
Struggling with the working rather than the topic itself? How to help your child with problem sums
See how your child is doing on this topic
StudyLah marks each step separately, so you can see whether it was the setup or the arithmetic that cost the mark.