Can dominoes cover the board?
A board, a chocolate bar or a floor of squares has two squares cut out, eaten or taken by plant pots. The student decides whether the rest can be covered exactly by 2-square dominoes or tiles, with no gaps and no overlaps.
Trying it out takes ages, but colouring settles it: every domino covers one dark and one light square. If the two missing squares are the same colour, there are more of one colour than the other, so it can't be done. If they are different colours, it can, and the working shows one way.
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What changes each time
- Boards from 4 by 4 to 6 by 6
- A board, a chocolate bar or a tiled floor
- Opposite corners, or any two squares not side by side
More shapes and angles practice
- Sides and corners of 2D shapes (Grade 2)
- Faces, edges and vertices (Grade 3)
- Sorting quadrilaterals (Grade 3)
- Turning and flipping letters (Grade 3)
- Counting squares of every size (Grade 3)
- Inside or outside the loop (Grade 3)
- Which piece fills the gap? (Grade 3)
- Symmetry on a grid (Grade 4)
- Rotations and reflections (Grade 4)
- Reading a protractor (Grade 4)
- Parallel and perpendicular lines (Grade 4)
- Parts of a circle (Grade 4)
- Draw without lifting your pencil (Grade 4)
- Can these sticks make a triangle? (Grade 4)
- 3D shapes: side view (Grade 5)
- Rectangle in a quarter circle (Grade 5)
- Painted cube puzzle (Grade 5)
- Rope around the Earth (Grade 5)
- Angles in a circle (Grade 6)
- Inscribed circle in a right triangle (Grade 8)