Math Operations and Expressions

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Video Lessons > Operations and Expressions in Math

Introduction and Video

In this video lesson, we will define and give examples of operations and expressions in math. We'll discuss the four main types of operations, look at examples of numeric and algebraic expressions, and introduce the process of simplifying expressions.

Lesson Notes for Operations and Expressions

Let's look at the details of the lesson to learn more about operations and expressions.

Types of Operations in Math

In math, operations are processes that allow us to solve problems, perform calculations, and manipulate numbers in various ways. There are four main operations that are commonly used: addition, subtraction, multiplication, and division.

  • Addition (+) is the operation of combining two or more numbers to find their total or sum. It is often represented by the plus sign (+). For example, adding 2 + 3 gives us a sum of 5.
  • Subtraction (-) is the operation of taking away one number from another to find the difference between them. It is often represented by the minus sign (-). For example, subtracting 7 - 3 gives us a difference of 4.
  • Multiplication (×) is the operation of repeated addition or combining equal groups to find the total number of items. It is often represented by the multiplication sign (×), as a dot (.), or with parentheses. For example, multiplying 4(3) gives us a product of 12.
  • Division (÷) is the operation of splitting a number into equal parts or finding out how many times one number can be divided by another. It is often represented by the division sign (÷) or as a fraction. For example, dividing 10/2 gives us a quotient of 5.

While there are other operations in math, such as exponents and square roots, these four operations are the most prevalent. They provide the foundation for more advanced math concepts and calculations.

The four main mathematical operations including addition, subtraction, multiplication, and division.

What are Expressions in Math?

An expression in mathematics is a combination of numbers, operations, and variables that represents a mathematical idea or relationship. It is a way to express a mathematical concept using symbols. These symbols can include numbers, operations, and variables.

Here are a few examples of mathematical expressions:

  • A numerical expression: 2 + 5
  • An algebraic expression with a variable and a number: 3y
  • An algebraic expression with variables: x/y

In all these examples, at least two elements (numbers or variables) are combined using a mathematical operation. Note that expressions with variables are called algebraic expressions while expressions with numbers and no variables are called numeric expressions.

Examples of mathematical operations and expressions. Includes numeric and algebraic expressions.

Simplifying Math Expressions

Simplifying an expression means rewriting it in the most concise or efficient form without changing its value. The goal is to make the expression easier to understand or work with.

Example: Consider the expression 2 + 5.

  • This expression represents the idea of adding five to two.
  • To simplify it, we perform the addition operation and combine the numbers 2 and 5.
  • The simplified expression becomes 7. The value of the expression remains the same, but it is now in a more concise form.

Simplifying is an important skill in math that allows us to work with complex expressions more easily. By simplifying an expression, we can focus on the essential elements and understand the underlying mathematical concept more effectively.

Defining the process of simplifying expressions. Example shown of simplifying a numeric expression.

Summary and Practice

In summary, understanding and manipulating operations and expressions are crucial skills in mathematics. They form the basis for more complex calculations and problem-solving strategies. By mastering these fundamental concepts, you can build a solid foundation for algebra and tackle more advanced topics with confidence.

Try this practice activity to see what you learned.

Video Transcript

In this lesson, we're going to look at operations and expressions. We'll review the operations that are used most commonly in math and we'll go over what expressions are as well as what it means to simplify an expression.

There are four main operations that we use in math and you've probably probably been using them for quite some time now. They include addition, subtraction, multiplication and division. There are a few other operations, but these are the four most common ones that we will see.

Next, let's talk about what an expression is. And when you hear the word expression, it might be used in a lot of different ways. For example, we can talk about someone's facial expression. Their facial expression shows or expresses how they may feel or think about something. They may smile to have a happy expression or frown to show a sad or an upset expression.

Well, in math, a mathematical expression is a mathematical idea that's represented with symbols. Those symbols may include numbers, operations like we just talked about, addition, subtraction, multiplication or division. And it can also include variables which are represented with letters.

So here's an example: two plus five. Now, you've seen problems like this many, many times, but you may not have thought of it as being a type of mathematical expression, but it does represent a mathematical idea. We're taking two of something and adding five more to it.

We can also mix numbers and variables together to form an expression. So with this one we have 3y, which even though we don't see a symbol there, represents multiplication. So the three and y are being multiplied together. And then we can also have different variables combined together in an expression.

Here we have x divided by y. But what we can see in all of these examples is that we have at least two different things, whether they're numbers or variables, and they're placed together using some type of operation, whether it's addition, multiplication or division.

Now we're going to talk about what it means to simplify an expression. Have you ever had a friend that tells really long stories and they go on and on and on and you just want to say, hey, can you hurry up and just give me the simplified version of the story?

It's kind of like that in math sometimes too. Sometimes we have really big, long expressions showing many different numbers and variables and operations, but we really just want to simplify it and make it easier to understand.

So when we're simplifying expressions, we're going to write the expression in the shortest or most efficient way. The result represents the same value as the original expression. So we haven't changed what the expression represents, we're just representing it in a shorter or more efficient way. And performing the operations that are shown in the expression will help us to simplify it.

So here's an example that we looked at before. Two plus five. Now, we know that two plus five is really just equal to seven. But what we're doing is simplifying that expression. We're performing the operation by adding the two and five together. Now, our result is just one number seven. So our original expression had two numbers in it, the two and five. But once we performed that addition operation, we were able to simplify it to just seven.

Related Standards: Common Core 4.OA.A.3, 5.OA.A.2, 6.EE.A.2

Hi, I'm Mia!

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