Cogito
Pre-K Math · Chapter 3 · Lesson 2
Triangles
Three sides, three corners.
10 problems · about 6 minutes · PK.G.1
What this lesson teaches
The child names triangles and counts their sides and corners.
- A triangle has three straight sides.
- It has three corners too.
- Triangles come in many shapes.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
5 problemsReview — Circles and Squares: How many corners does a square have?
Answer 4
Why Four.
Review — Counting a Jumble: How many? ●●●●●●●●
Answer 8
Why Eight.
Review — Zero Means None: Nothing on the table. How many?
Answer 0
Why Zero.
Review — One More: One more than 7?
Answer 8
Why Eight.
Review — Nine and Ten: How many fingers on two hands?
Answer 10
Why Ten.
Warm Up
Straightforward practice. Get the method working first.
2 problemsHow many corners does a triangle have?
Answer 3
Why Three.
How many sides does a triangle have?
Answer 3
Why Count them.
Build It Up
The same ideas with more to keep track of.
1 problemHow many corners does a triangle have?
Answer 3
Why Same as the sides.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsWhich has more sides, a triangle or a square?
Answer A square.
Why Four beats three.
The Roof: A shape has three sides. What is it?
Answer A triangle.
Why A triangle.