Fun with Shapes (Preparatory Stage Math)
Worksheet A: Concepts
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Square, triangle, and curved-line petals/arcs.
Solution
Rangoli on dot grids mixes straight-edged polygons (squares/triangles) and curved motifs, as shown in the chapter prompts on dot patterns and naming shapes.
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Rectangles and squares.
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Cuboid faces trace as rectangles; a cube’s faces trace as squares; flattening shows face shapes on the net clearly.
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All sides equal in a square; only opposite sides equal in a rectangle.
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Both have four right corners, but equality of all four sides holds only for squares, not for general rectangles.
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The longest fold-line is a diameter; fold lines meet at the center.
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Folding in half produces diameters; their intersection marks the center of the circle clearly.
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Square: flat only; Rectangle: flat only; Circle (disc face): curved edge but flat face; Cylinder (solid): both flat (two circles) and curved (side).
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Polygons have flat edges/faces; a cylinder combines flat circular faces with a curved lateral surface in 3D.
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Rectangles; no triangular faces.
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A cuboid’s six faces are rectangles (some may be equal squares); triangles don’t occur as faces on a cuboid.
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Both have 4 sides; both have 4 square corners (right angles).
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They are quadrilaterals with right angles at each corner and straight sides forming closed shapes.
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Make an L with strips; if both edges align with table edges without gaps, it’s a square corner.
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Two perpendicular strips model a right angle; matching to an object corner checks if it is a square corner.
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Similarity: both use dot-grid symmetry; Difference: one has more straight-edged squares, the other uses curved petals.
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Visual patterns can share structure yet differ by edge types, demonstrating multiple design choices on dots.
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Yes for both; square and rectangle corners are all right angles and match on piling.
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Right angles are congruent; superposing corners demonstrates equality for all corners in these shapes.
Worksheet B: Computational Skills
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6 (three 1×1, two 1×2, one 1×3).
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Combine adjacent small rectangles to form longer ones; count by lengths 1, 2, and 3.
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Cube: 6 faces, 8 corners; Cuboid: 6 faces, 8 corners.
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Both are 3D with six flat faces and eight vertices; face shapes differ (squares vs rectangles).
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Two pairs; opposite sides are equal.
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Left equals right, top equals bottom; adjacent sides can differ in length.
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4 sides, 4 corners; all sides equal.
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A square is a special rectangle with all sides same and right corners.
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10 and 15.
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Triangular numbers add row lengths 1+2+3+…; next sums are 1+2+3+4=10 and +5=15.
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8 sticks.
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Each right angle uses two sticks; four separate corners total eight sticks.
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Three concentric squares.
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Original plus two larger around it creates three total nested squares on the grid.
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They must be at equal offsets forming equal opposite sides and parallel pairs.
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Construct from the midpoint and equal horizontal/vertical distances to ensure parallel, equal opposite sides.
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18 total (6 small 1×1, 4 of 1×2 per row ×2 rows = 8, 2 of 1×3 per row ×2 rows = 4, plus 2 of 2×1 per column ×3 columns = 6? Adjust: correct method gives 18 by combinations C(3+1,2)*C(2+1,2)=C(4,2)*C(3,2)=6*3=18).
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Choose two vertical grid lines and two horizontal grid lines: combinations count all possible rectangles systematically.
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With 2 squares: 1 domino; with 3 squares: 2 trominoes (straight and L).
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Edge-joining squares creates polyominoes; up to rotation/reflection there is one 2-omino and two 3-ominoes.
Worksheet C: Problem-Solving & Modeling
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A triangular flap; starting with a square ensures even folds.
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Square symmetry makes opposite corners meet; folded corner creates a triangle flap that closes neatly.
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Book cover, whiteboard, eraser face (examples).
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Many everyday solids expose rectangular faces; tracing confirms the shape property in context.
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Right-angle wedge; square.
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Square corners are right angles; a right-angled tile fits exactly into the corner.
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Center; diameter.
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Intersecting diameters reveal the center; a diameter is the circle’s longest straight chord.
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Examples vary; justification must cite square vs curved corners/edges.
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Differentiate by presence of right angles vs curves; attribute-based sorting supports reasoning.
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Pick pieces whose straight edges align to make opposite sides equal and parallel.
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Edge matching and equal length ensure the completed outline remains a rectangle with right corners.
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Examples vary; one shape may have a line of symmetry, the other may not.
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Joining right triangles yields varied polygons; properties differ by arrangement (symmetry/angles).
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Curved, straight.
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Repeat the two-step motif; ABAB… gives the next terms by alternation.
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5 (four 1×1, one 2×2 formed by a 2×2 block if present; for an L of 4 without 2×2 block, total is 4 only—explain based on layout).
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Check if any 2×2 completes; in a pure L tetromino, no full 2×2 appears, so only four 1×1 squares.
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Yes; edges must join without gaps/overlaps using all seven pieces.
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Tangram admits rectangle solutions; alignment requires full use of pieces and straight boundary edges.
Two best activities
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Create two versions of the same rangoli on dot grids: one with mostly straight edges, one with curved arcs; then compare.
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Provide dot sheets and shape cutouts/strings. Learners draw Version A with squares/rectangles/triangles; Version B with arcs/petals. Discuss similarities (symmetry, repeats) and differences (edge types, corners), linking to chapter tasks on rangoli, naming shapes, and comparing designs.
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Open real boxes to nets, trace faces, label corners, then rebuild paper models (cube/cuboid), and test corners with the strip right-angle tool.
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Learners flatten small boxes to see rectangles/squares in nets, count faces/corners, rebuild as prisms, and verify right corners using two paper strips. Extend by folding a paper-plate circle to mark center/diameters, and by tracing rectangular faces on objects in class for a display wall.