Cogito
Grade 1 Math · Chapter 9 · Lesson 6
Halves
Cut a whole into two equal shares.
10 problems · about 13 minutes · 1.G.A.3
What this lesson teaches
The child partitions circles and rectangles into two equal shares, names them halves, and rejects unequal splits.
- Two equal shares are called halves.
- Equal means exactly the same size.
- Two halves make one whole.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
5 problemsReview — Shapes Inside Shapes: How many triangles make one trapezoid?
Answer 3
Why A trapezoid is 3 triangles.
Review — Making New Shapes: How many triangles fill one hexagon?
Answer 6
Why It takes 6 triangles.
Review — 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.
Warm Up
Straightforward practice. Get the method working first.
3 problemsHow many equal shares are in a half?
Answer 2
Why A half is one of 2 equal shares.
What must be true about halves?
Answer They are the same size.
Why Halves must be equal shares.
How many halves make one whole?
Answer 2
Why Put both pieces back.
Build It Up
The same ideas with more to keep track of.
1 problemAre two pieces halves if one is bigger?
Answer No. They must be equal.
Why Halves must be the same size.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
1 problemSharing a Pizza: Two friends share a pizza fairly. How many shares?
Answer 2 shares
Why Two equal shares are called halves.