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 → Length ↓


Comparing and Ordering Lengths


In Grade 3, we begin to understand the concept of length and how to compare and order different lengths. Length is a measure of how long something is from one end to the other. In our everyday lives, length can be seen in the height of a building, the size of a pencil, or the distance between two places.

Units of length

Before we can compare and order lengths, we need to understand the units of length we use in measurement. The most common units of length are inches, feet, centimeters, and meters. Here's how they are related:

1 foot = 12 inches
1 meter = 100 centimeters
1 inch is about 2.54 centimeters
1 foot is about 0.3048 meters

These units help us measure length in a consistent way so that everyone can easily understand and compare measurements.

Learning to measure length

We often use a ruler or tape measure to measure length. Here's how you can measure the length of an object using a ruler:

  1. Place the ruler along the object so that the zero mark is at one end of the object.
  2. Look at the end of the object to see the measurement on the ruler.
  3. Read the number to find the length of the object.

Understanding how to compare lengths

When we compare lengths, we look at two or more objects to find out which object is longer, which is shorter or they have the same length. Let us consider some examples:

Example 1: Comparing the length of pencils

Imagine you have two pencils. One pencil is 7 inches long, and the other pencil is 5 inches long. You can compare these pencils by simply looking at the numbers:

Pencil A: 7 inches
Pencil B: 5 inches

Since 7 is greater than 5, pencil A is longer than pencil B.

Example 2: Comparing lengths of ribbons

Suppose you have two ribbons. One ribbon is 30 centimeters long, and the other is 45 centimeters long:

Ribbon A: 30 centimeters
Ribbon B: 45 centimeters

Here, 45 is greater than 30, so ribbon B is longer than ribbon A.

Length order

Putting lengths in order means arranging them from shortest to longest or longest to shortest. Let's look at some examples:

Example 3: Ordering sticks by length

Imagine you have three sticks with the following lengths: 9 inches, 14 inches, and 11 inches. You can arrange them in order from shortest to longest:

9 inches, 11 inches, 14 inches

Alternatively, you can sort them from longest to shortest:

14 inches, 11 inches, 9 inches

Example 4: Sorting strings by length

You have three strings. Their lengths are 50 cm, 70 cm and 65 cm. To arrange them from shortest to longest:

50 centimeters, 65 centimeters, 70 centimeters

To arrange them from longest to shortest:

70 centimeters, 65 centimeters, 50 centimeters

Practical activities to understand length

Participating in practical activities helps to better understand length and measurement. Here are some simple activities you can do:

Activity 1: Measuring classroom objects

  1. Pick up items in the classroom such as books, pencil cases, and rulers.
  2. Measure the length of each object using a measuring tape or ruler.
  3. Write down your measurements on a piece of paper.
  4. Compare lengths and sort objects from shortest to longest.

Activity 2: Making a measuring collage

  1. Collect small objects like paper clips, erasers, and toys.
  2. Create a table on a large piece of paper with two columns labeled "Object" and "Length."
  3. Measure each object and record its length in the table.
  4. Cut a strip of paper to the length of each object and make a collage by arranging the strips from shortest to longest on another chart paper.

Using number lines to compare lengths

The number line can be used as a helpful tool for visualizing and comparing lengths. You can draw a number line on paper and plot the lengths like this:

0 50 15 cm 35 cm

Understanding equal length

Sometimes two objects can have the same length. This means they are the same size when measured from one end to the other.

Example 5: Comparing equal lengths

Consider two rulers, each measuring 30 centimeters:

Ruler A: 30 centimeters
Ruler B: 30 centimeters

In this case, both rulers are of equal length, that is, none is longer or shorter than the other.

Using everyday situations to practice

There are lots of everyday scenarios where you can practice comparing and ordering lengths:

  • Compare the length of vegetables while cooking and decide which ones need to be cut for even cooking.
  • When shopping compare the sizes of different items to see which will best fit your home.
  • Compare the height of slides or the length of swings for safety on the playground.

Interactive exploration of lengths

Using interactive activities online or in mobile apps can also help to better understand length. These activities can include games where you compare lengths to find matching objects or sorting exercises with visual feedback.

Conclusion

Comparing and ordering lengths is an essential skill that helps us understand the environment around us and make informed decisions. By practicing with different objects and units of measurement, we can develop a strong foundation in measurement and enhance our problem-solving skills. Always remember to make accurate measurements and think about how lengths compare to one another. The more you practice, the more comfortable you will become with the concepts of length and measurement.


Grade 3 → 3.1.2


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Measuring in Centimeters and Meters
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Estimating Lengths

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Comparing and Ordering Lengths

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