Understanding Nets of Solids (PSLE Math)
A geometry net is a 2-dimensional (2D) shape that can be folded to form a 3-dimensional (3D) shape or a solid.
In other words, when you fold a 2D shape which is flat like a piece of paper, you will get a 3D solid like a piece of cube.
On the other hand, if you unfold a cube below, you will get the net of the cube as shown below.
However, is this the only net of a cube?
There are 11 of them, and your child needs to know all of them.
11 Nets of a Cube
As you can see, I have grouped them into 3 groups.
The first group is the 1-4-1 net which means 1 squares, followed by 4 squares, followed by 1 square.
The first 4 are derived from a Capital T, by just moving the last square downwards.
The other 2 are derived from a Small T, by moving the last square downwards.
However, when you move the last square all the way to the bottom, it is the same as the 3rd net by rotating it 180 degrees.
The same principal applies for the 1-3-2 net by moving the first square downwards.
For the 3-3 and 2-2 net. there is only 1 net for each group as you cannot adjust them.
Other than nets of cube, your child also need to know nets of other solids.
Nets of Cuboid
Nets of Pyramid
Nets of Triangular Prism
Instead of memorising them, your child can try to label one of the shape as the base. From there, he can visualise folding the net in his mind and try to see if he can get the solid formed.
I understand that this may not be easy. So the easiest way is to take a piece of paper, draw the squares on it, cut out the net, and fold it with his own hands.
Of course, in the exams, it is not possible to cut paper. So the better option is to train the mind to visualise using the earlier method.
Many parents think that it may be gifted talent that some children can visualise better than others. But let me assure you that Mastery only comes with…
With deliberate practice, your child will be able to Master every topic of Math, no matter how hard it is.
And your child needs to practise deliberately. If he is weak in Nets, do at least 10 questions on Nets until he is able to solve all of them.
Most importantly, he needs to know the concepts first. Without knowing the concepts, your child will be memorising answers which is certainly not the way to study Math.