Nets and cubes
A net is six squares that fold up into a cube, and you find which face ends up opposite another. Here's how to do it without folding.
Chapter 1
What are nets and cubes questions?
A net is a cube opened out flat: six squares joined edge to edge, like a cereal box cut along its edges and laid on the table.
One square of the net is ringed. You pick the face that ends up opposite it when the net folds back into a cube. Opposite means the far side: the floor is opposite the ceiling.
At the hardest level the question changes: you’re shown five shapes, and only one of them folds into a cube. Chapter 3 shows you how to spot it.
Which face ends up opposite the ringed one?
An NVR question from Rush, level 1.
Chapter 2
Solve it in 4 steps.
Steps 1 to 3 solve the question. Step 4 is for the nets where step 3 can’t reach.
The question
Which face ends up opposite the ringed one?
An NVR question from Rush, level 1.
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Step 1
Find the ringed face.
Put your finger on it. Here it’s white, at the right-hand end of a row of four: orange, blue, red, white.
White is ringed.
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Step 2
Cross out the faces that touch it.
Squares that share a whole edge in the net end up side by side on the cube, so they can never be opposite. Red shares an edge with white: cross it out.
Red shares an edge with white.
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Step 3
In a straight line, skip one.
Count along the line from white: jump over the square next to it (red) and land on the one after (blue). Blue is opposite white. It works across or down, whichever way has a square to land on.
Just the row: jump over red, land on blue.
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Step 4
No line to skip along? Find the zigzag.
A zigzag is a straight row, across or down, with one square sticking out at each end, on opposite sides. Those two end squares are opposite. Here, orange sticks up from one end and purple down from the other.
Up, along, down: orange and purple are opposite.
Watch it fold
The row rolls round into the four walls of the cube, and the squares above and below it become the lid and the base. White and blue end up facing each other.
White is ringed. Along the row, skip one: past red to blue.
Fold the row up.
White and blue end up facing each other: opposite.
Purple is ringed. Follow the zigzag to its other end: pink.
Fold it up.
The two ends of the zigzag face each other: opposite.
Three mistakes on this net
| The mistake | Do this instead |
|---|---|
| Picking the far end of the row. Orange looks furthest from white. But a row of four rolls round, and its two ends meet side by side. | Jump over one square: the one after it is opposite. |
| Skipping one round a corner. White, red, pink looks like skip-one, but the path bends at red. Pink folds up into the lid, right next to white. | Skip one only in a dead straight line. |
| Only looking along the row. If pink were ringed, there’s nothing to its left or right. But pink, red and purple make a straight line going down. | Skip one down a column too: pink jumps over red and lands on purple. |
So it’s blue, option 3. Blue is one skip along the row from white, so it folds round to the far side.
Remember: Never touch. Skip one. Z ends.
Chapter 3
When it gets harder.
The same rules still work. Here’s how to use them on the trickier nets, and on the hardest question of all.
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Every face has exactly one partner
A cube has three pairs of opposite faces. Here: A is white and blue, B is red and orange, C is pink and purple. If two options are already a pair, neither can be the answer.
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Zigzags come in every shape
The row in the middle can be short, and it can go down. Here it’s only red and blue, going down: orange sticks out at the top and white at the bottom, so they’re opposite.
Which shape folds into a cube?
At the hardest level you’re shown five shapes and only one is a net. Run four checks, quickest first. A shape that fails any one of them can’t fold into a cube.
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Check 1
Is there a 2 × 2 block?
Four squares in a square fold onto each other. Cross the shape out.
A 2 × 2 block: not a net.
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Check 2
Five in a straight line?
A cube is only four squares round, so a fifth square in a line wraps back onto the first.
Five in a row: not a net.
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Check 3
Two squares on the same side of one row?
Two squares joined straight onto the same side of a row, like the sides of a U, both fold onto the same face.
Like a U: not a net.
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Check 4
Does any face get two partners?
Pair up the opposites with skip-one and the zigzag. If one square ends up with two partners, two faces would have to land in the same place.
The corner is skip-one from both ends: two partners, so not a net.
All 11 nets of a cube
Every shape that passes the four checks is one of these eleven. Turning one round or flipping it over doesn’t make a new one. Six of them have a row of four with one square above and one below.
Six nets have a row of four, one square above it and one below.
Three have a row of three, two squares on top and one below.
Then two rows of three, and the staircase.
That makes 11. Any other six squares won't fold into a cube.
Chapter 4: In the exam
Which cube does the net make?
Most 11+ papers that test nets show a net with a pattern on every face and ask which drawn cube it folds into. Rush doesn’t ask this one, but the same rules, plus two more checks, crack it.
Which cube can this net make?
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Check 1
Is every pattern on the net?
Cube 2 shows a triangle. There’s no triangle on the net, so cube 2 is out.
1 2 3 4 5 -
Check 2
Are two opposite faces showing?
A drawn cube shows three faces that meet at a corner, so no two of them can be opposite. In the net, the dot and the plus are a skip-one pair. Cube 1 shows both: out.
1 2 3 4 5 -
Check 3
Does each pattern point the right way?
Any pattern that looks different when turned (an arrow, a triangle, a half-shaded square) must point at the same neighbour as in the net. The arrow points at the square, so on the cube it points up at it. Cube 4’s points away: out.
1 2 3 4 5 -
Check 4
Is each neighbour on the right side?
In the net, with the arrow pointing up at the square, the plus is on the arrow’s right and the dot on its left. So with the square on top, the plus must be on the right. Cube 5 has the dot there: it’s the mirror image, so it’s out.
1 2 3 4 5
So it’s cube 3. Every pattern is on the net, no opposites touch, the arrow points up at the square, and the plus is on its right.
Remember: Missing? Opposite? Which way? Which side?
Other ways the exam asks it
- “Which cube could not be made?” Same checks, but now you want the cube that fails one. Underline “not” before you start.
- “Which net makes this cube?” Run the checks the other way round: on each net, find the cube’s three faces, check none of them are opposite, then check which way they point and which side they’re on.
- “Which face is opposite …?” That’s chapter 2: never touch, skip one, Z ends.
Chapter 5
Try it yourself.
Six real questions from Rush, easy to hard, 60 seconds on the clock.
Use the steps
- Find the ringed face.
- Cross out the faces that touch it.
- In a straight line, skip one.
- No line to skip along? Find the zigzag.
Remember: Find it. Never touch. Skip one.
For parents.
More on nets and cubes, and what parents ask us.
More on nets and cubes
Nets of other solids
Shape Facts, one of Rush's maths games, shows nets of prisms and pyramids and asks which solid they make. A prism's net has two matching ends joined by a strip of rectangles; a pyramid's has one base with a triangle on each side.
Questions parents ask
How do you solve cube net questions?
Start from the ringed face and cross out every face that touches it. Then look along a straight row (skip one square, and the next is opposite) or follow a zigzag (the two ends are opposite). Neither needs any folding in your head.
How many nets does a cube have?
Eleven, but your child doesn't need to learn them by heart. The four checks in chapter 3 (no 2 × 2 block, no five in a row, no two squares on the same side of a row, and every face with exactly one partner) rule out the other 24 six-square shapes, and never rule out a real net.
What if my child can't picture it folding?
That's what the rules are for. Skip-one and the zigzag ends do the folding for you, so nothing has to be imagined in 3D. Folding a paper net once or twice, with the faces coloured in, helps them trust the rules.
Do skip-one and the zigzag work on every net?
Yes. Each of the 11 nets has three pairs of opposite faces, and on every one of them skip-one and the zigzag ends find all three pairs. If neither seems to fit at first, look for a zigzag going down as well as across: the row in the middle can be as short as two squares.
Rush: 11+ Practice & KS2 SATsPractise nets and cubes in Rush.
- Cube Nets and Shape Facts as 100-second games, easy at first and harder as your child improves
- Every miss kept with the right answer and why
- Cube Nets and Shape Facts are in Premium, and six other games are free
On the App Store for iPhone and iPad
Six other games are free, plus a new family game every day. Cube Nets and Shape Facts are in Premium: all 41 games are £24.99 a year after a free week1, or £3.99 a month.