Cogito
Grade 1 Math · Chapter 9 · Lesson 2
Naming Flat Shapes
Learn the names of the flat shapes you see everywhere.
10 problems · about 12 minutes · 1.G.A.1
What this lesson teaches
The child names circles, triangles, rectangles, squares, trapezoids, rhombuses, and hexagons in varied sizes and orientations.
- The number of sides gives the shape its name.
- A hexagon has 6 sides. A circle has none.
- Turning a shape never changes its name.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
4 problemsReview — 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.
Review — Adding Two-Digit Numbers: 21 + 14 = ?
Answer 35
Why 3 tens and 5 ones is 35.
Review — Word Problems Within 40: Whole 35, one part 15. Other part?
Answer 20
Why 35 − 15 = 20.
Warm Up
Straightforward practice. Get the method working first.
3 problemsA shape has 6 straight sides. What is it?
Answer A hexagon.
Why 6 sides makes a hexagon.
How many sides does a trapezoid have?
Answer 4
Why A trapezoid has 4 sides.
How many sides does a hexagon have?
Answer 6
Why Count around the outside.
Build It Up
The same ideas with more to keep track of.
1 problemHow many sides does a circle have?
Answer 0
Why A circle is round all the way.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsHow many corners does a square have?
Answer 4
Why One at each turn.
Shapes at School: A window has 4 sides and 4 square corners. What is it?
Answer A rectangle.
Why 4 sides and square corners make a rectangle.