Grade 2
  1. Number Sense and Operations  1.1. Counting and Number Sequences  1.1.1. Counting up to 100  1.1.2. Counting by 2s, 5s, and 10s  1.1.3. Counting Backward from 20  1.1.4. Odd and even numbers in counting sequences  1.2. Place Value  1.2.1. Understanding ones and tens  1.2.2. Comparing Two-Digit Numbers  1.2.3. Identifying the Value of Each Digit in a Number  1.2.4. Building numbers using tens and ones  1.3. Addition and Subtraction  1.3.1. Basic addition up to 20  1.3.2. Basic subtraction up to 20  1.3.3. Addition with Regrouping  1.3.4. Subtraction with Borrowing  1.3.5. Solving word problems involving addition and subtraction  1.3.6. Addition and Subtraction with Multiples of 10  1.4. Odd and Even Numbers  1.4.1. Identifying Odd and Even Numbers  1.4.2. Understanding patterns in odd and even numbers  1.4.3. Simple operations with odd and even numbers
  2. Fractions and Decimals  2.1. Introduction to Fractions  2.1.1. Understanding halves and quarters  2.1.2. Representing fractions visually  2.1.3. Simple Fraction Comparisons  2.1.4. Writing Simple Fractions  2.1.5. Fractions as part of a whole  2.2. Fraction Equivalency  2.2.1. Understanding Equal Parts  2.2.2. Identifying Equivalent Fractions
  3. Measurement and Data  3.1. Length Measurement  3.1.1. Measuring objects using rulers  3.1.2. Comparing lengths  3.1.3. Estimating lengths  3.1.4. Understanding units of measurement (centimeters and inches)  3.1.5. Relating Length Measurements to Real-World Objects  3.2. Weight and Mass Measurement  3.2.1. Comparing Weights of Objects  3.2.2. Estimating weight in grams and kilograms  3.2.3. Using balance scales for comparison  3.3. Volume and Capacity Measurement  3.3.1. Understanding capacity with cups and liters  3.3.2. Comparing capacities of containers  3.3.3. Introduction to Milliliters  3.4. Time  3.4.1. Reading analog and digital clocks  3.4.2. Understanding hours and minutes  3.4.3. Calculating elapsed time in hours  3.4.4. Days of the week and months of the year  3.4.5. Understanding AM and PM  3.5. Money  3.5.1. Recognizing coins and bills  3.5.2. Counting money up to $1  3.5.3. Simple Addition and Subtraction with Money  3.5.4. Making Change for a Dollar
  4. Geometry and Spatial Reasoning  4.1. Shapes and Their Attributes  4.1.1. Identifying basic shapes (circle, triangle, square, rectangle)  4.1.2. Understanding sides and corners  4.1.3. Distinguishing between 2D and 3D shapes  4.1.4. Recognizing 3D Shapes (Cube, Sphere, Cone, Cylinder)  4.1.5. Composing and Decomposing Shapes  4.2. Symmetry  4.2.1. Understanding Lines of Symmetry  4.2.2. Drawing Symmetrical Shapes  4.2.3. Identifying Symmetrical Objects in the Environment  4.3. Patterns and Spatial Awareness  4.3.1. Recognizing and Creating Patterns  4.3.2. Extending Patterns  4.3.3. Understanding positions (left, right, above, below)  4.3.4. Using a grid to locate objects
  5. Data Handling and Probability  5.1. Collecting and Organizing Data  5.1.1. Using tally marks  5.1.2. Reading Bar Graphs  5.1.3. Simple Pictographs  5.1.4. Creating Bar Graphs from Given Data  5.2. Interpreting Data  5.2.1. Answering questions based on data  5.2.3. Identifying Most and Least in Data Sets  5.3. Introduction to Probability  5.3.1. Understanding likely and unlikely events

Grade 2 → Geometry and Spatial Reasoning → Shapes and Their Attributes ↓


Understanding sides and corners


Geometry is a fun and exciting branch of mathematics. In second grade, we begin to explore the basics of geometry to better understand the shapes around us. Every shape has sides and corners, and knowing about these helps us identify and describe shapes correctly. Let’s take a deeper look at what sides and corners are and how they work in different shapes.

What are the sides?

The sides of a shape are the straight lines that form the outline of the shape. You can think of the sides as the edges of the shape. If you draw a line around a shape with a pencil, you are drawing a line around its sides.

Visual example:

Consider a triangle. A triangle is a simple figure with three sides. Let's look at this through a visual representation:




A
B
C

This triangle ABC has sides AB, BC and CA. These names come from connecting the points of the triangle: A to B, B to C and C to A.

Text example:

Let's take a square. A square has four sides. Each side is the same length. The sides might look like this:

  • Side 1: 5 cm
  • Side 2: 5 cm
  • Side 3: 5 cm
  • Side 4: 5 cm

Since all sides of a square are equal, that's one feature that helps you identify it as a square.

What are corners?

The corners of a shape are where two sides meet. Each corner of a shape is called a vertex (plural vertices). Corners are like the 'points' of a shape.

Visual example:

Consider a rectangle. A rectangle has four corners because it has four sides. Here is a visualization of a rectangle:




I
F
Yes
H

This rectangle EFGH has four corners E, F, G and H where the sides meet.

Text example:

An easy example of this is a pentagon. A regular pentagon has five corners. You can think of it like this:

  • Corner 1: Point A
  • Corner 2: Point B
  • Corner 3: Point C
  • Corner 4: Point D
  • Corner 5: Point E

Each point is where two sides of the pentagon meet.

Joining sides and corners

Every closed figure can be identified by its sides and corners. The number of sides in a figure will be equal to the number of its corners. This helps us to name and identify the figure correctly.

Examples of common shapes:

Triangle

A triangle has 3 sides and 3 corners. Here's a simple formula to remember:

Sides of Triangle = 3 Corners of Triangle = 3
Sides of Triangle = 3 Corners of Triangle = 3

Social class

A square has 4 sides and 4 corners. You can use a simple rule:

Sides of Square = 4 Corners of Square = 4
Sides of Square = 4 Corners of Square = 4

Rectangle

A rectangle also has 4 sides and 4 corners. Remember:

Sides of Rectangle = 4 Corners of Rectangle = 4
Sides of Rectangle = 4 Corners of Rectangle = 4

Pentagon

A pentagon has 5 sides and 5 corners. Like this:

Sides of Pentagon = 5 Corners of Pentagon = 5
Sides of Pentagon = 5 Corners of Pentagon = 5

Hexagon

A hexagon has 6 sides and 6 vertices. Maintain this relationship:

Sides of Hexagon = 6 Corners of Hexagon = 6
Sides of Hexagon = 6 Corners of Hexagon = 6

Real-life examples of shapes

We come across various shapes in our daily life. Let's look at some shapes with sides and corners:

Triangle

  • Pyramid design
  • Road signs such as 'leave' signs
  • Pizza slices

Social class

  • Squares of the chessboard
  • Tiles on the floor
  • Some houses have windows

Rectangle

  • Smart fone
  • Door frames
  • Television screen

Pentagon

  • Decorative tiles
  • Pentagon building in America
  • Fruits and stars (such as starfish)

Hexagon

  • Beehives
  • Patterned tiles and decor
  • Pencils (cross-section view)

Why it is important to understand sides and corners

Understanding sides and corners helps us in several ways:

  • Describing shapes: Knowledge of sides and corners allows you to describe and differentiate between different shapes. For example, "This is a shape that has four equal sides and four corners - it must be a square!"
  • Geometry skills: Recognizing and counting sides and corners lays a strong foundation for future geometric learning and reasoning, which is important in advanced math.
  • Problem Solving: Understanding shapes helps solve puzzles and problems effectively by visualizing and manipulating shape components such as sides and corners.
  • Design and Construction: Knowing the basics about edges and corners helps in drawing, building, or designing simple structures or art, thereby boosting creativity and innovation.

Conclusion

In the journey of learning mathematics, understanding shapes is fundamental. Sides and corners form the essence of geometric shapes, and understanding these concepts leads to deeper mathematical exploration. When exploring the world around us, it becomes essential to relate the number of sides and corners to the name and type of shapes. This knowledge connects to real-life situations, from simple designing to complex problem-solving.

As we learn, practice and explore geometry, we can see how basic concepts such as sides and corners spark curiosity to innovate, observe and appreciate the diverse world of shapes around us. Whether you are drawing, building or simply noticing the shapes around you, this understanding strengthens the love and appreciation for mathematics, making learning enjoyable and practical.


Grade 2 → 4.1.2


U
username
0%
completed in Grade 2

← Prev (4.1.1)
Identifying basic shapes (circle, triangle, square, rectangle)
Next (4.1.3) →
Distinguishing between 2D and 3D shapes

Comments 



Understanding sides and corners

https://www.buddymath.com/g2/4.1.2?bmal=en