CCSS.Math.Content.1.G.A.2
The standard
Compose two-dimensional shapes (rectangles, squares, trapezoids, triangles, half-circles, and quarter-circles) or three-dimensional shapes (cubes, right rectangular prisms, right circular cones, and right circular cylinders) to create a composite shape, and compose new shapes from the composite shape.
Common Core State Standards for Mathematics · Geometry
What this standard means
Students need to put simple shapes together to make larger shapes, then see that the larger shape can be used as part of a new shape. They should work with flat shapes like triangles, squares, rectangles, trapezoids, half-circles, and quarter-circles, and solid shapes like cubes, prisms, cones, and cylinders.
Mastery looks like a student saying, "I used two triangles to make a square," or "This cube tower can be part of a building." Students often get stuck when shapes are turned sideways, when two shapes make an unfamiliar outline, or when they focus on color and size instead of shape attributes.
Ways to teach it
- Give pairs pattern blocks or paper cutouts and ask them to make a house, boat, or animal using at least four shapes.
- Ask students to explain, in words or pictures, how two smaller shapes can make one bigger shape.
- Show a composite shape and ask students to circle the smaller shapes they see inside it.
- Have students find classroom objects made from combined shapes, such as a cylinder pencil cup with rectangular labels.
Plan a lesson for CCSS.Math.Content.1.G.A.2
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Related standards
- CCSS.Math.Content.6.G.A.1
Find the area of right triangles, other triangles, special quadrilaterals, and polygons by composing into rectangles or decomposing into triangles and other sha...
- CCSS.Math.Content.K.G.B.6
Compose simple shapes to form larger shapes.
- CCSS.Math.Content.K.G.B
Analyze, compare, create, and compose shapes.
- CCSS.Math.Content.K.G.A
Identify and describe shapes (squares, circles, triangles, rectangles, hexagons, cubes, cones, cylinders, and spheres).