Grade 1 › G1U09 2-D Shapes

Grade 1 › G1U09 2-D Shapes › L3
GRADE 1 · ALBERTAOUTCOME AB-G1-1G1

L3 · Building new shapes: composing and decomposing

Learning goal

“I can join shapes to build a new shape, and take a shape apart to see its parts.”

Join — to put shapes together so they touch and make one new shape.
Take apart — to split a shape into the smaller shapes it was made from.
Part — one smaller piece of a bigger shape.
Worked example

Take two squares. Join them along one full side, side to side. Step 1: The two squares touch along a whole side. Step 2: The touching sides hide inside the new shape. Step 3: The new shape is long: it has 2 long sides and 2 short sides. It is a rectangle. Say it plainly: when you join shapes, the sides that touch hide inside. The outside of the new shape is what you name.

Check yourself — explain it

Two squares join side to side. What new shape do they make?

Paired problem — example still visible

Join a triangle on top of a square, like a roof on a house. What does your picture look like? -> A house (a square with a triangle roof)

Faded completion — last step is yours

"Two squares joined side to side make a long ___" -> rectangle

Ready to practise?

8 scored questions with a 3-rung hint ladder. Mastery needs 7/8 plus both gate questions.

Start practice →Take the unit quiz