Cube Nets

How to play Cube Nets

• Look at the net on the screen and answer the question. Each round has 10 questions, and you get your score and time at the end. After you answer, the net folds itself into a cube so you can see why, and you can drag the cube to turn it around.
• Easy: “Does this net fold into a cube?” Answer yes or no. Of the 35 shapes you can make by joining six squares edge to edge, only 11 fold into a cube.
• Medium: Tap the face that ends up opposite ★. When the net has dice dots, pick the number that goes on “?” (opposite faces of a die add up to 7).
• Hard: Tap the edge that meets the thick edge when the net is folded. Look for the outer edge that ends up touching it.
• Daily: 5 questions a day (1 easy, 2 medium and 2 hard), the same for everyone. There’s a new set every day.
• 11 nets: Pick any of the 11 nets of a cube and fold or unfold it bit by bit with the slider. Turn on the dice dots to see that opposite faces always add up to 7.
• On a computer, answer yes or no with Y and N (or 1 and 2, or ← and →), type 1 to 6 for a number, and choose a face or an edge with the arrow keys and Enter. Press Enter for the next question. If you close the page, you can pick up where you left off.

• Printable cube net templateDice templates with glue tabs, at actual size. All 11 nets, ¾–1¾ in

The 11 nets of a cube

There are 35 different shapes made of six squares joined edge to edge (called hexominoes), but only 11 of them fold into a cube. Shapes that match after turning or flipping count as the same net. The names count the squares in each row: 1-4-1 has a row of four with one square above and one below (6 nets), 2-3-1 has rows of two, three and one (3 nets), 2-2-2 is a staircase of three pairs (1 net), and 3-3 is two rows of three (1 net). Tap a net to fold it in the puzzle above.

How to tell if a net folds into a cube

• In a straight row, every other face is opposite. Two faces with one face between them (the 1st and 3rd, or the 2nd and 4th) end up opposite each other. The two ends of a row of four end up side by side.
• The ends of a Z are opposite. In a Z or N shape of four faces, two and two like a step, the two end faces end up opposite each other.
• In a 1-4-1 net, the top and bottom faces are opposite. The square above the row of four and the square below it are always opposite, wherever along the row they are attached.
• A 2×2 block never folds into a cube. Neither does a row of five or more squares. Some faces would overlap.
• Each face has only one opposite. Use the rules above. If a face ends up with two opposite faces, the shape is not a net of a cube.
• On a die, opposite faces add up to 7. 1 is opposite 6, 2 is opposite 5, and 3 is opposite 4. Once you know which faces are opposite, you can work out a missing number.
• At an inside corner, the two edges meet. Where three squares meet in an L, the two edges on either side of the inside corner join up when you fold it. If you’re not sure, watch where each edge goes as the net folds after you answer.

What is a net of a cube?

A net is what you get when you cut a solid along some of its edges and lay it out flat. A cube is made of six squares, and depending on which edges you cut, you get one of 11 different nets. A dice net is the same thing with dots on the faces. Because a net is just the six faces laid flat, its area equals the surface area of the cube: 6 × side × side.

Nets are part of school geometry, and spatial reasoning tests often ask which faces end up opposite and which edges or corners meet. If folding in your head is hard, watching a few nets fold here is the quickest way to get the hang of it.