Grade 3
  1. Number Sense and Numeration  1.1. Understanding Numbers  1.1.1. Reading and Writing Numbers up to 10,000  1.1.2. Place Value up to Thousands  1.1.3. Comparing and Ordering Numbers  1.1.4. Rounding Numbers to the Nearest Ten and Hundred  1.1.5. Skip Counting by 2s, 5s, 10s, and 100s up to 1,000  1.2. Operations with Whole Numbers  1.2.1. Addition and Subtraction up to 1,000  1.2.2. Multiplication Facts (up to 10 x 10)  1.2.3. Division Facts (up to 100)  1.2.4. Multiplication as Repeated Addition  1.2.5. Division as Equal Sharing  1.2.6. Word Problems with Addition, Subtraction, Multiplication, and Division  1.3. Estimation  1.3.1. Estimating Sums and Differences  1.3.2. Estimating Products and Quotients  1.4. Understanding Even and Odd Numbers
  2. Fractions and Decimals  2.1. Understanding Fractions  2.1.1. Identifying and Representing Fractions  2.1.2. Fractions of a Whole and Part of a Set  2.1.3. Comparing and Ordering Fractions with Like Denominators  2.1.4. Equivalent Fractions  2.1.5. Simple Fraction Word Problems  2.2. Introduction to Decimals  2.2.1. Tenths and Hundredths as Decimals  2.2.2. Relationship between Fractions and Decimals
  3. Measurement  3.1. Length  3.1.1. Measuring in Centimeters and Meters  3.1.2. Comparing and Ordering Lengths  3.1.3. Estimating Lengths  3.1.4. Converting Between Centimeters and Meters  3.2. Mass  3.2.1. Measuring in Grams and Kilograms  3.2.2. Estimating and Comparing Mass  3.3. Capacity  3.3.1. Measuring in Milliliters and Liters  3.3.2. Estimating and Comparing Capacity  3.4. Time  3.4.1. Telling Time to the Nearest Minute  3.4.2. Calculating Elapsed Time  3.4.3. Using a Calendar  3.4.4. Understanding A.M. and P.M.  3.5. Area and Perimeter  3.5.1. Calculating Perimeter of Simple Shapes  3.5.2. Estimating and Measuring Area of Shapes  3.5.3. Finding Area by Counting Squares
  4. Geometry  4.1. Properties of Shapes  4.1.1. Identifying 2D Shapes (Triangles, Quadrilaterals, Circles, etc.)  4.1.2. Identifying 3D Shapes (Cubes, Spheres, Cylinders, etc.)  4.1.3. Describing Attributes of 2D and 3D Shapes  4.1.4. Recognizing Parallel and Perpendicular Lines  4.2. Symmetry and Transformations  4.2.1. Recognizing Lines of Symmetry  4.2.2. Identifying Flips, Slides, and Turns  4.3. Angles  4.3.1. Understanding Right Angles  4.3.2. Comparing Angles (Acute, Right, Obtuse)
  5. Data Management and Probability  5.1. Data Collection and Organization  5.1.1. Collecting Data using Surveys and Experiments  5.1.2. Organizing Data using Tally Charts and Tables  5.2.1. Creating and Interpreting Pictographs  5.2.2. Creating and Interpreting Bar Graphs  5.2.3. Reading Simple Line Graphs  5.3. Probability  5.3.1. Understanding Basic Probability Terms (Certain, Possible, Impossible)  5.3.2. Predicting Outcomes  5.3.3. Simple Probability Experiments
  6. Patterns and Algebra  6.1. Patterns  6.1.1. Identifying and Extending Numeric Patterns  6.1.2. Identifying and Extending Shape Patterns  6.1.3. Creating Patterns Using Rules  6.2. Introduction to Algebra  6.2.1. Understanding Variables as Unknowns  6.2.2. Solving Simple Addition and Subtraction Equations  6.2.3. Using Patterns to Solve Problems
  7. Problem-Solving Skills  7.1. Strategies for Problem-Solving  7.1.1. Using Pictures or Diagrams  7.1.2. Identifying Patterns in Problems  7.1.3. Making Organized Lists  7.1.4. Guessing and Checking  7.1.5. Using Logical Reasoning  7.1.6. Breaking Down Problems into Steps

Grade 3 → Measurement → Area and Perimeter ↓


Estimating and Measuring Area of Shapes


Learning how to estimate and measure the area of shapes is a basic skill in math for grade 3 students. This skill helps lay the foundation for more complex concepts in geometry and measurement as students progress through their education. In this explanation, we will explore what area means, how it can be estimated, and ways to measure it accurately. We will provide examples using simple shapes like squares and rectangles, and even look at more irregular shapes. Let's dive into this topic step by step!

What is the area?

Area is the amount of space inside a shape. It tells us how much space the shape takes up or how much space it has. Imagine a flat surface, such as a table. Area is how much of the table is taken up by the shape.

Understanding the concept of area through memory and imagination

Think of a lawn in your backyard. If you want to cover it completely with grass tiles, the number of tiles you will need will depend on the area of your lawn. If each tile is 1 square foot, the total number of tiles will be equal to the area of the lawn.

Simple visualization example

Consider a rectangle that is 4 units long and 3 units wide. To estimate the area, you can fill this rectangle with blocks that measure 1 unit by 1 unit:

,
,
,

You can see that there are 4 blocks above and 3 blocks below, a total of 12 blocks. Each block represents one square unit, so the area of this rectangle is 12 square units.

Estimating the area

Estimating area involves making a guess about the number of square units inside a shape. Estimating is useful when exact measurements are not possible.

Example: Estimating the area of a polygon

Consider a hexagon. Although it is difficult to calculate the exact area without specific formulas, we can imagine that it fits inside a larger rectangle. Count how many full square units fit inside the hexagon and make a reasonable estimate for any partial squares.

Measuring area

Measuring area accurately involves counting how many 1-unit by 1-unit squares fit into the shape without overlaps or gaps. For many basic shapes, we have formulas that can help us do this quickly.

Rectangle area formula

The formula for finding the area of a rectangle is to multiply its length by its width:

Area = length × breadth

For a rectangle that is 5 units long and 2 units wide, you use the following formula:

Area = 5 × 2 = 10 square units

Example: Measuring the area of a square

Since all sides of a square are equal, the formula for finding its area is:

Area = side × side

If the length of the side of a square is 4 units:

Area = 4 × 4 = 16 square units

Interactive example with shapes

Let's look at some more shapes:

What if the task is to find the area of a rectangle that is 7 units by 3 units?

Area = 7 × 3 = 21 square units

For a square with side length 6:

Area = 6 × 6 = 36 square units

Exploring irregular shapes

Sometimes, shapes are irregular and do not fit into the standard formulas for rectangles or squares. When this happens, we often break these shapes down into familiar shapes, calculate each shape's area, and then combine the results.

Example: Estimating the area of an irregular shape

Imagine an L-shaped figure. Break it into two rectangles. Find the area of each and add them together.

Rectangle 1 (4 × 2) = 8 square units
Rectangle 2 (3 × 2) = 6 square units
Total area = 8 + 6 = 14 square units

Another example with steps

Suppose you have a complex shape with a different number of straight edges. Estimate by counting the full and half squares.

The figure is as follows:

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,
,

Assuming that some partial squares can be combined to form a complete square, each part is visually assigned either a complete or partial region, thereby producing an estimation.

Practical exercise: Measuring area in real life

Practical exercises are a great way for children to internalise these concepts. Task them with measuring objects around the house such as a book cover, picture frame or even a smartphone using grid paper.

Practical activity

Ask students to draw different areas on graph paper and count the squares. Choosing specific dimensions allows for tactile learning experiences and helps reinforce understanding.

Summary of the learning process

Estimating and measuring area is an important milestone in grade 3 math. The ability to estimate helps when exact measurements aren't possible, and knowing how to accurately calculate area supports future learning in geometry and design.

Remember, practice is essential to build confidence in using these concepts. Encourage the use of tools such as rulers, grid paper, and eventually more advanced software to provide different levels of challenge and engagement.

Conclusion

This educational journey of estimating and measuring area introduces students to the fundamentals of space and dimension. As they learn and practice these skills, they develop a better understanding of the world around them, which prepares them for more complex mathematical concepts in the future.


Grade 3 → 3.5.2


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Calculating Perimeter of Simple Shapes
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Finding Area by Counting Squares

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Estimating and Measuring Area of Shapes

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