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 → Number Sense and Numeration ↓


Estimation


Understanding the concept of assessment

Estimating in math is an important skill that helps us make good guesses or approximate calculations without needing exact answers. In Grade 3, students begin learning to use estimation to solve problems in everyday situations. Estimating is like a magical tool that gives us a quick answer that is pretty close to the actual answer.

So why do we use estimation? Imagine you are at the supermarket, and you want to know if you have enough money to buy five apples, each of which costs about $0.85. Instead of calculating it all out on paper or with a calculator, you can quickly estimate the total cost using estimation. This way, you can make decisions quickly and efficiently.

Basic techniques of assessment

Rounding off numbers

One of the most common techniques for estimating is rounding numbers. Rounding numbers to make them simpler helps make calculations easier. For example, if we have the number 73 and we want to estimate, we can round it to the nearest ten, which would be 70. When using rounding in estimating, the general rule is:

If the score is 5 or more then round it up.
If the score is less than 5, round it down.

Let’s look at some examples!

Rounding off examples:

  • 13 is rounded off to 10 because the digit 3 is smaller than 5.
  • 58 is rounded off to 60 because the digit 8 is greater than 5.
  • 81 is rounded to 80 because the digit 1 is smaller than 5.

Estimating the amount

When adding numbers, estimating can help us figure out what the total will be. To estimate the sum, we can first round the numbers and then add them.

Approximate sum of 47 + 76:

Step 1: Round each number to the nearest ten.

  • From 47 to 50
  • 76 to 80 rounds

Step 2: Add the rounded numbers.

50 + 80 = 130

So the approximate sum of 47 + 76 is 130.

50 80 130

Estimating the difference

Just like addition, we can estimate the difference when subtracting numbers. The process is the same; we first round off each number, then subtract.

Estimating the difference of 91 - 34:

Step 1: Round each number to the nearest ten.

  • From 91 to 90
  • 30 out of 34 rounds

Step 2: Subtract the rounded numbers.

90 - 30 = 60

Therefore, the approximate difference of 91 - 34 is 60.

90 30 60

Benefits of assessment

Estimating isn't just a mathematical skill; it's a valuable life skill. Here are some of its benefits:

  • Speed: Allows for quick calculations when time is limited.
  • Comprehension: Improves understanding of number size and place value.
  • Confidence: Making math more accessible builds confidence.
  • Problem solving: Develops skills in decision making and problem solving by providing predictable outcomes to guide choices.

Everyday examples of inference

Shopping

When shopping, you can use estimation to figure out how much you're spending. Instead of remembering exact prices, round them up and add them up as you shop to see how close you are to your budget.

If you buy:

  • One book costs $14.99, up to $15
  • One toy for $7.49, about $7
  • A bottle of water for $1.29, about $1

Estimated Total Cost: $15 + $7 + $1 = $23

Cooking

Estimating is also useful in the kitchen. If you're making a recipe that calls for 2.5 cups of flour, you can estimate that it will be about 2 or 3 cups, depending on which type of flour you like best. This skill is especially useful when you don't have measuring tools!

Of travel

When traveling, perhaps by car, you can estimate how long it will take to reach your destination. If you are traveling 50 miles and driving about 50 miles per hour, you can estimate that it will take you about an hour to get there.

Travel time estimates for a trip at about 60 mph:

  • Distance: 180 miles

Estimated time: 180 ÷ 60 ≈ 3 hours

Practice exercises

Here are some exercises for you to learn the art of estimation:

Exercise 1: Rounding

Round off the following numbers to the nearest ten:

  • 27
  • 43
  • 86
  • 91

Exercise 2: Estimating amounts

To find the sum of these numbers, round each to the nearest ten and then add:

  • 36 + 48
  • 67 + 24

Exercise 3: Estimating the difference

Estimate the difference for each of these problems by rounding off each number and then reducing it:

  • 72 - 29
  • 95 - 36

Conclusion

Estimating is a simple but powerful tool that not only aids calculations but also builds confidence in handling numbers. As Grade 3 students understand and practice these skills, they will find math less scary and more practical for daily use. Estimating makes them flexible thinkers ready to tackle real-world math challenges! Encourage them to practice estimating regularly, and soon, they will find it second nature. Enjoy estimating!


Grade 3 → 1.3


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Word Problems with Addition, Subtraction, Multiplication, and Division
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Estimating Sums and Differences

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Estimation

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