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 → Time ↓


Calculating Elapsed Time


In the world of mathematics, measuring time is an essential skill. It is important to understand how to calculate elapsed time. Elapsed time is the time that passes from the start of an event to its end. It is important in our everyday lives - from scheduling an appointment to catching the bus on time.

Understanding the basics of time

Time is measured in different units such as hours, minutes and seconds. The most common units we use in everyday life are hours and minutes. There are 60 minutes in an hour and 24 hours in a day.

Time conversion example

1 hour = 60 minutes

2 hours = 120 minutes

3 hours = 180 minutes

What is the elapsed time?

Elapsed time is basically the same as the difference between two times. It's about finding out how long something lasts. For example, if you start reading at 3:00 PM and stop reading at 4:30 PM, you need to find out how much time you spent reading.

Example of elapsed time calculation

Start Time: 3:00 PM

End time: 4:30 PM

Time spent: 1 hour 30 minutes

How to calculate elapsed time

There are several steps you can follow to find the time elapsed between two events.

Step 1: Look at the hours

First, look at the hour component of the time. Subtract the hour of the start time from the hour of the end time.

<code>
Last hour - Start hour = Elapsed hours
4 - 3 = 1 hour
</code>

Step 2: Look at the minutes

Next, look at the minutes component. Subtract the minutes of the start time from the minutes of the end time.

<code>
Last minute - Start minute = Elapsed minute
30 - 00 = 30 minutes
</code>

Step 3: Combine the hours and minutes

Finally, combine the hours and minutes to get the total elapsed time.

Let’s look at another example!

Example

Start time: 2:15 PM

End time: 5:45 PM

Step 1: Find the hours elapsed. 5 - 2 = 3 hours

Step 2: Find the minutes elapsed. 45 - 15 = 30 minutes

Total time spent: 3 hours and 30 minutes

Visualization of the past

Visual depictions can help make sense of the past.

3:00 pm 4:30 PM

In the visualization above, the green rectangle represents the start time at 3:00 PM, and the blue rectangle represents the end time at 4:30 PM. The length between them represents the elapsed time.

More examples of past time

Example 1

Start time: 11:00 am

End time: 1:15 PM

Time spent: 2 hours and 15 minutes

11:00 AM 1:15 PM

Using the above visualization, the time elapsed from 11:00 AM to 1:15 PM is 2 hours and 15 minutes, represented by a combination of gray and light steel-blue parts.

Example 2

Start time: 9:45 am

End time: 12:30 PM

Time spent: 2 hours and 45 minutes

9:45 AM 12:30 PM

The above scene shows a total time period of 2 hours and 45 minutes from 9:45 AM to 12:30 PM, represented by tomato and dark sky blue color areas.

Practice problems

Below are some practice problems to test your understanding. Try to count the elapsed time for each one.

  • Problem 1: Start time: 7:20 AM, End time: 10:05 AM
  • Problem 2: Start time: 1:50 PM, End time: 4:30 PM
  • Problem 3: Start time: 6:00 PM, End time: 9:45 PM

Conclusion

Understanding how to count elapsed time is a valuable life skill. With practice, you can determine how much time has passed between any two events. Remember to use steps: focus on hours, then minutes, then combine them. Use visual aids whenever possible to help you understand concepts better. Keep practicing, and you'll become a pro at counting elapsed time!


Grade 3 → 3.4.2


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Telling Time to the Nearest Minute
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Using a Calendar

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Calculating Elapsed Time

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