Cogito
Grade 2 Math · Chapter 8 · Lesson 5
Halves
Two equal shares of one whole.
10 problems · about 11 minutes · 2.G.A.3
What this lesson teaches
The child partitions circles and rectangles into halves and names one share.
- 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.
4 problemsReview — Cubes and Solid Shapes: How many faces does a cube have?
Answer 6
Why A cube has 6 square faces.
Review — Shapes by Their Sides: A shape has 6 straight sides. What is it?
Answer A hexagon.
Why 6 sides makes a hexagon.
Review — A.M. and P.M.: Is 3 o’clock in the afternoon a.m. or p.m.?
Answer p.m.
Why Afternoon times are p.m.
Review — Time to Five Minutes: The long hand is on the 5. How many minutes past?
Answer 25
Why The 5 means 25 minutes.
Warm Up
Straightforward practice. Get the method working first.
3 problemsHow many halves make one whole?
Answer 2
Why Two halves make a whole.
What must be true about halves?
Answer They are the same size.
Why Halves must be equal shares.
How many equal shares make halves?
Answer 2
Why Two of them.
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 Two pieces is not enough on its own.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsThe Sandwich: A sandwich is shared equally between 2 people. What is each share called?
Answer A half.
Why One of two equal shares is a half.
Putting It Back: How many halves make one whole?
Answer 2
Why Two halves make one whole.