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 → Operations with Whole Numbers ↓


Addition and Subtraction up to 1,000


Welcome to the world of numbers, where we are going to learn how to add and subtract whole numbers up to 1,000. It is important to understand these concepts, as they are the cornerstone for more complex mathematical operations. This journey involves looking at numbers in different ways and understanding how they interact. Let's get started!

Understanding the numbers

Before we start adding or subtracting, we need to understand numbers. Numbers up to 1,000 are made up of three digits: hundreds, tens, and ones. For example, the number 456 has these:

  • 4 centuries
  • 5 tens
  • 6 one

Let's take a look at the number 729:

    hundreds | tens | units
    ,
        7 | 2 | 9

This means that 729 has 7 hundreds, 2 tens, and 9 units.

Increment up to 1,000

When we add numbers, we put them together to find their sum. Let's start simple by adding two-digit numbers and then move on to three-digit numbers.

Basic example - Two-digit addition

    45 + 32

Step 1: Add

    5 + 2 = 7

Step 2: Add the tens

    40 + 30 = 70

Now add the results of the ones and tens places together.

    70 + 7 = 77

Your final answer is 77.

Adding three-digit numbers

Adding three-digit numbers is similar to two-digit addition, but now we need to add the hundreds as well.

Example: Add 256 + 473

      256
    +473

Step 1: Add

    6 + 3 = 9

Step 2: Add the tens

    50 + 70 = 120

Step 3: Add the hundreds

    200 + 400 = 600

Now combine all these values:

    600 + 120 + 9 = 729

So, 256 + 473 equals 729.

Subtraction up to 1,000

Subtraction is the process of subtracting one number from another. Like addition, we will start with two-digit numbers and then move on to three-digit numbers.

Basic example - Two-digit subtraction

    78 - 34

Step 1: Subtract the units

    8 - 4 = 4

Step 2: Subtract the tens

    70 - 30 = 40

Now combine the results:

    40 + 4 = 44

Your final answer is 44.

Subtracting three-digit numbers

Now, let's subtract three-digit numbers. Sometimes this involves borrowing when the top digit is smaller than the bottom digit.

Example: Subtract 685 - 297

      685
    - 297

Step 1: Subtract the units

Since 5 is less than 7, we have to borrow. Convert 5 into 15 by borrowing 1 tenth from 80, which makes it 70.

    15 - 7 = 8

Step 2: Subtract the tens

Now after borrowing, 70 is left, so:

    70 - 90 = -20 (borrow 1 from hundreds)

Borrow 1 hundred: now 600 becomes 500, and 70 becomes 170:

    170 - 90 = 80

Step 3: Subtract the hundreds

    500 - 200 = 300

Combine the results:

    300 + 80 + 8 = 388

So, 685 - 297 equals 388.

Visual example

It helps to represent these problems using blocks or diagrams.

Yoga using blocks

Let's imagine 123 + 456. Imagine blocks where each block is a local value:

3 one 2 tens 1 hundred 6 one 5 tens 4 centuries

Subtracting using blocks

Let's look at 532 - 214 with blocks:

2 one 3 tens 5 centuries 4 one 1 ten 2 centuries

When you subtract, you remove gray blocks from the colored blocks from left to right. After you remove, see what's left.

Practice problems

Here are some problems to test your skills:

  1. 248 + 759
  2. 510 - 375
  3. 633 + 298
  4. 821 - 446

Try solving these yourself. Use paper and pencil or visual methods to help.

Conclusion

Mastering addition and subtraction with numbers up to 1,000 is crucial to developing your math skills. By understanding place values, you can solve both simple and complex problems with confidence. Keep practicing and remember that numbers are your friend, helping you explore the world of math with more confidence.


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Addition and Subtraction up to 1,000

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