Cogito
Grade 1 Math · Chapter 9 · Lesson 4
Making New Shapes
Put small shapes together to build a bigger one.
10 problems · about 13 minutes · 1.G.A.2
What this lesson teaches
The child composes two-dimensional shapes to build a target composite shape, and finds more than one way to do it.
- Small shapes can build a bigger shape.
- The pieces must fill it with no gaps.
- The same shape can be built in more than one way.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
4 problemsReview — Naming Solid Shapes: A can of soup is shaped like what?
Answer A cylinder.
Why A can is a cylinder.
Review — Naming Flat Shapes: A shape has 6 straight sides. What is it?
Answer A hexagon.
Why 6 sides makes a hexagon.
Review — What Makes a Shape a Shape?: How many corners does a triangle have?
Answer 3
Why 3 sides make 3 corners.
Review — When the Ones Make a Ten: 16 + 17 = ?
Answer 33
Why 2 tens and 13 ones becomes 3 tens and 3 ones.
Warm Up
Straightforward practice. Get the method working first.
3 problemsHow many triangles fill one hexagon?
Answer 6
Why It takes 6 triangles.
Can pieces leave gaps?
Answer No. They must fill it exactly.
Why Pieces must fill the shape with no gaps.
How many triangles fill a hexagon?
Answer 6
Why Count them in the picture.
Build It Up
The same ideas with more to keep track of.
1 problemHow many rhombuses fill a hexagon?
Answer 3
Why Each covers two triangles.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsHow many squares fill this rectangle?
Answer 2
Why Count the pieces in the picture.
Pattern Blocks: How many trapezoids fill one hexagon?
Answer 2 trapezoids
Why 2 trapezoids fill a hexagon exactly.