2nd Grade Addition and Subtraction: Key Terms and Facts Every Student Should Know

Introduction: Why 2nd Grade math matters

Before understanding what addition and subtraction mean, we must determine why 2^nd Grade matters.

First, math is everywhere in our lives. We use it to count, measure, compare, and more. Also, it helps us make sense of the world and solve problems. That's why it's important to learn math well and enjoy it.

In 2nd grade, you will learn more about numbers and how to use them differently. You will also learn how to add and subtract numbers up to 1000. These are essential skills that you will use throughout your life.

Addition: What it means and how to do it

The addition is one of the basic operations in math. It means combining two or more numbers to get a bigger number. For example, if you have 3 apples and 4 oranges, add them together to get 7 fruits.

The symbol for addition is +. To add two numbers, you must line them up according to their place values (ones, tens, hundreds, etc.) and then add each pair of digits from right to left. If a pair of digits sum is 10 or more, you must carry the extra digit to the next place value.

For example:

In this example, we start by adding the ones: 7 + 6 = 13. Since this is more than 10, we write 3 in the ones place and carry over 1 to the tens place.

Then we add the tens: 1 + 3 + 5 = 9. We write 9 in the tens place.

Finally, we add the hundreds: 2 + 4 = 6. We write 6 in the hundreds place.

The final answer is 693.

Subtraction: What it means and how to do it

Subtraction is another basic operation in math. It means taking away one number from another number to get a smaller number. For example, if you have 7 candies and eat 4 of them, you can subtract them to find out how many candies you have left.

The symbol for subtraction is -. To subtract two numbers, you need to line them up according to their place values (ones, tens, hundreds, etc.) and then subtract each pair of digits from right to left. If the digit on the top is smaller than the digit on the bottom, you must borrow a digit from the next place value.

In this example, we start by subtracting the ones: 3 - 6 = -3. Since this is negative, we borrow a digit from the tens place and make it 13 - 6 = 7. We write 7 in the ones place and reduce the tens place by one.

Then we subtract the tens: 8 - 5 = 3. We write 3 in the tens place.

Finally, we subtract the hundreds: 5 - 4 = 1. We write 1 in the hundreds place.

The final answer is 237.

Facts: Basic rules and strategies for addition and subtraction

There are some facts or basic rules and strategies that you need to know for addition and subtraction. These facts help you do math faster and more accurately.

Here are some of the most important facts:

• The commutative property means that you can change the order of the addends without changing the answer.

For example, 3 + 4 = 4 + 3.

• The associative property means that you can change the grouping of the addends without changing the answer. For example, (3 + 4) + 5 = 3 + (4 + 5).
• The identity property means that adding zero or subtracting zero does not change the number. For example, 3 + 0 = 3 and 3 - 0 = 3.
• Inverse property means that adding the opposite or subtracting the same number gives zero. For example, 3 + (-3) = 0 and   3 - 3 = 0.
• Addition and subtraction facts: These are the basic combinations of numbers that you need to memorize. For example, you need to know that 2 + 2 = 4, 5 - 3 = 2, etc.

Knowing these facts will help you do math faster, mentally, and more confidently.