Grade 2
  1. Number Sense and Operations  1.1. Counting and Number Sequences  1.1.1. Counting up to 100  1.1.2. Counting by 2s, 5s, and 10s  1.1.3. Counting Backward from 20  1.1.4. Odd and even numbers in counting sequences  1.2. Place Value  1.2.1. Understanding ones and tens  1.2.2. Comparing Two-Digit Numbers  1.2.3. Identifying the Value of Each Digit in a Number  1.2.4. Building numbers using tens and ones  1.3. Addition and Subtraction  1.3.1. Basic addition up to 20  1.3.2. Basic subtraction up to 20  1.3.3. Addition with Regrouping  1.3.4. Subtraction with Borrowing  1.3.5. Solving word problems involving addition and subtraction  1.3.6. Addition and Subtraction with Multiples of 10  1.4. Odd and Even Numbers  1.4.1. Identifying Odd and Even Numbers  1.4.2. Understanding patterns in odd and even numbers  1.4.3. Simple operations with odd and even numbers
  2. Fractions and Decimals  2.1. Introduction to Fractions  2.1.1. Understanding halves and quarters  2.1.2. Representing fractions visually  2.1.3. Simple Fraction Comparisons  2.1.4. Writing Simple Fractions  2.1.5. Fractions as part of a whole  2.2. Fraction Equivalency  2.2.1. Understanding Equal Parts  2.2.2. Identifying Equivalent Fractions
  3. Measurement and Data  3.1. Length Measurement  3.1.1. Measuring objects using rulers  3.1.2. Comparing lengths  3.1.3. Estimating lengths  3.1.4. Understanding units of measurement (centimeters and inches)  3.1.5. Relating Length Measurements to Real-World Objects  3.2. Weight and Mass Measurement  3.2.1. Comparing Weights of Objects  3.2.2. Estimating weight in grams and kilograms  3.2.3. Using balance scales for comparison  3.3. Volume and Capacity Measurement  3.3.1. Understanding capacity with cups and liters  3.3.2. Comparing capacities of containers  3.3.3. Introduction to Milliliters  3.4. Time  3.4.1. Reading analog and digital clocks  3.4.2. Understanding hours and minutes  3.4.3. Calculating elapsed time in hours  3.4.4. Days of the week and months of the year  3.4.5. Understanding AM and PM  3.5. Money  3.5.1. Recognizing coins and bills  3.5.2. Counting money up to $1  3.5.3. Simple Addition and Subtraction with Money  3.5.4. Making Change for a Dollar
  4. Geometry and Spatial Reasoning  4.1. Shapes and Their Attributes  4.1.1. Identifying basic shapes (circle, triangle, square, rectangle)  4.1.2. Understanding sides and corners  4.1.3. Distinguishing between 2D and 3D shapes  4.1.4. Recognizing 3D Shapes (Cube, Sphere, Cone, Cylinder)  4.1.5. Composing and Decomposing Shapes  4.2. Symmetry  4.2.1. Understanding Lines of Symmetry  4.2.2. Drawing Symmetrical Shapes  4.2.3. Identifying Symmetrical Objects in the Environment  4.3. Patterns and Spatial Awareness  4.3.1. Recognizing and Creating Patterns  4.3.2. Extending Patterns  4.3.3. Understanding positions (left, right, above, below)  4.3.4. Using a grid to locate objects
  5. Data Handling and Probability  5.1. Collecting and Organizing Data  5.1.1. Using tally marks  5.1.2. Reading Bar Graphs  5.1.3. Simple Pictographs  5.1.4. Creating Bar Graphs from Given Data  5.2. Interpreting Data  5.2.1. Answering questions based on data  5.2.3. Identifying Most and Least in Data Sets  5.3. Introduction to Probability  5.3.1. Understanding likely and unlikely events

Grade 2 → Number Sense and Operations ↓


Addition and Subtraction


Understanding addition and subtraction is important for young students to build a strong foundation in math. In this comprehensive lesson, we will explore the concepts of addition and subtraction taught in Grade 2. We will explain these concepts in simple terms, offering both text and visual examples to aid understanding.

What is yoga?

Addition is a way to get a total or sum by combining two or more numbers. It is represented by the plus sign (+). For example, if you have 2 apples and you find 3 more apples, you can use addition to find out how many apples you have in total. It looks like this:

 2 + 3 = 5

In this equation, 2 and 3 are called the summaries, and 5 is called the addend.

Visual example of addition

, ,

As shown in this picture, when you combine 2 blue squares and 3 red squares, you get 5 green squares.

Properties of yoga

There are certain properties of yoga that help us understand and solve yoga problems more efficiently:

Commutative property

The commutative property of addition states that changing the order of addition does not change the sum. For example:

 3 + 5 = 8
 5 + 3 = 8

No matter what order you put the numbers in, the sum will be the same.

Associative property

According to the associative property of addition, when three or more numbers are added together, the grouping of the numbers does not affect the sum. For example:

 (1 + 2) + 3 = 6
 1 + (2 + 3) = 6

You can group the numbers differently, and the sum will still be the same.

Identity property

The identity property of addition states that any number greater than zero is equal to the original number. For example:

 6 + 0 = 6

Adding zero to a number does not change its value.

What is subtraction?

Subtraction is a way of subtracting one number from another. It is represented by the minus sign (-). For example, if you have 5 apples and you give 3 away, you can use subtraction to figure out how many apples you have left. It looks like this:

 5 - 3 = 2

In this equation, 5 is the subtraction, 3 is the subtraction, and 2 is called the difference.

Visual example of subtraction

, ,

As shown in this picture, when you remove 3 red squares from the 5 blue squares, you are left with 2 green squares.

Regrouping in subtraction

Sometimes, subtraction requires regrouping, also known as borrowing. Let's see how this works with an example:

If you want to subtract 14 from 32:

          32
        - 14
        ,

The 2 in the ones place is smaller than 4, so you need to borrow 1 from the tens place:

         2 (makes 12)
        (2) (3 - 1 = 2)
        ,
          18

By borrowing, you turn the 3 in the tens place into a 2, and the 2 in the ones place into 12. Now you can subtract: 12 - 4 = 8 and 2 - 1 = 1. So, 32 - 14 = 18.

Practising addition and subtraction

Practice is key to mastering addition and subtraction. Here are some fun examples and exercises to try:

Example 1: Adding Numbers

 8 + 7 = ?

Think about it this way: 8 + 2 = 10. Now you need to add 5 more (because 7 = 2 + 5), so 10 + 5 = 15. Thus, 8 + 7 = 15.

Example 2: Subtracting numbers

 15 - 9 = ?

Think of it as getting up to 10 first: 15 - 5 = 10. You've effectively subtracted 5, so we need to subtract 4 more (because 9 = 5 + 4). Now, 10 - 4 = 6, so 15 - 9 = 6.

Exercise 1

  • 5 + 3 = ?
  • 9 - 6 = ?
  • 7 + 7 = ?
  • 10 - 4 = ?

Exercise 2

Solve these using regrouping:

  • 13-8 = ?
  • 21-15 = ?

Conclusion

Understanding addition and subtraction is an important step in becoming proficient in math. These are fundamental skills that students will use throughout their education and everyday life.

Remember, addition means adding numbers to get a bigger number, and subtraction means subtracting a number from another to make it smaller. Practice these skills often to improve accuracy and speed.

By using models, regrouping, and the properties of addition and subtraction, students will develop strong arithmetic skills that are essential for future math work. Keep practicing, and over time, these concepts will become second nature.


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Addition and Subtraction

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