Lesson Guide
Explanation
A net is a 3-D shape flattened: a cube's net is 6 connected squares that fold back into the box. The most useful net to know is the CROSS: four squares in a row with one hanging above and one below — it always folds into a cube. Not every arrangement of 6 squares works: some fold two faces onto the same spot and leave a hole. OC questions rarely ask 'does it fold' alone — they ask about the FACES: which numbers end up opposite, touching, or where. That's the next step's game.
Your Turn
Picture the cross net folding: the 4-in-a-row squares wrap around to make the sides; the up-and-down squares become… what? Check: the top and bottom.
Watch Out
A 2×3 block of six squares does NOT fold into a cube — squares overlap. Connected isn't enough.
Explanation
The power tool: finding opposite faces WITHOUT folding. In any straight line of squares on a net, faces that are one apart (skip a square) end up opposite on the cube. In the cross net numbered 1-2-6-5 across, 1 is opposite 6 and 2 is opposite 5; the hanging pair (3 and 4) are opposite each other. And a guarantee to lean on: squares that TOUCH on the net share an edge on the cube — touching squares can never be opposite. Skip-one → opposite; touching → neighbours. Those two facts solve most net questions in seconds.
Your Turn
Net row reads 2-4-5-1. Which face is opposite the 2? Check: 5 — skip one along the row.
Watch Out
The skip-one rule works along STRAIGHT lines of the net. Around corners, faces wrap differently — fold those in your head carefully.
Explanation
A typical question: which of four nets folds into a NORMAL dice — one where opposite faces add to 7 (1↔6, 2↔5, 3↔4)? Method per option: find the three opposite pairs using the skip-one rule, check each sums to 7, and one failure eliminates the net. The speed hack: scan for a FORBIDDEN TOUCH first. If 1 and 6 share an edge anywhere on the net, they can't be opposite — but a normal dice needs them opposite, so that net dies instantly. Touching 1-6, 2-5 or 3-4 anywhere = eliminate without folding a thing. Usually three options die by forbidden touches and the survivor wins.
Your Turn
A net has 3 and 4 side by side in its row. Can it be a normal dice? Check: no — 3 and 4 must be opposite (3+4=7), but touching faces are neighbours.
Watch Out
Check ALL the pair sums on your chosen answer, not just one — examiners build nets where two pairs work and the third fails.
Explanation
When a question needs the full fold — 'which face touches face X?' — use ANCHOR AND WRAP. Pick one face (say B) and nail it down as the bottom. Its row-neighbours fold up into walls, the skip-one face wraps over to become the top, and hanging squares fold into the remaining walls. The discipline: move ONE fold at a time away from the anchor, never all six at once. Most students who 'can't visualise' are trying to see the whole cube in one go; anchored folding is a chain of single, easy moves.
Your Turn
Cross net, centre square anchored as bottom. Where does the square directly above the centre end up? Check: a wall (side face), sharing an edge with the bottom.
Watch Out
In test pressure, mark the anchor face with your finger on screen or scratch paper — losing the anchor mid-wrap is how folds go wrong.
Explanation
The net toolkit: skip-one along a straight line → opposite faces; touching squares → neighbours, never opposite; the forbidden-touch scan eliminates dice nets instantly (a touching 1-6, 2-5 or 3-4 can't make a normal dice); and anchor-and-wrap for full folds. One real-world tip that beats any trick: cut a cross net from paper and fold it ONCE at home. Five minutes with scissors makes every test net question feel obvious — your hands teach your eyes. Quiz and exercises!
Your Turn
Capstone: a net row reads 6-2-1-5, with 3 above the 2 and 4 below. Normal dice? Check: 6 opposite 1 (=7 ✓), 2 opposite 5 (=7 ✓), 3 opposite 4 (=7 ✓) — yes!
Watch Out
The test shows dice faces as dot patterns, not digits — count dots carefully; 6-dot and 4-dot faces blur at speed.
📌 Key Points — this lesson in a nutshell
- A cube net is 6 connected squares that fold without overlapping; the cross net always works.
- Skip-one rule: faces one apart in a straight net line become OPPOSITE on the cube.
- Touching squares on the net share an edge on the cube — they can never be opposite.
- Normal dice: opposite faces add to 7 (1↔6, 2↔5, 3↔4).
- Forbidden-touch scan: a net where 1-6, 2-5 or 3-4 touch cannot make a normal dice — instant elimination.
- For full folds, anchor one face as the bottom and wrap one step at a time.
Step 1: Introduction
Step 1 of 5
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