Main content

### Course: 6th grade > Unit 6

Lesson 8: Writing algebraic expressions introduction- Writing basic expressions with variables
- Writing algebraic subtraction expressions
- Writing basic expressions with variables
- Writing basic expressions with variables
- Writing expressions with variables
- Writing expressions with parentheses
- Writing expressions with variables & parentheses
- Writing expressions with variables
- Writing expressions with variables

© 2024 Khan AcademyTerms of usePrivacy PolicyCookie Notice

# Writing basic expressions with variables

Learn to write expressions with variables in math! Discover how to represent various operations like addition, subtraction, multiplication, and division using variables. Master the art of creating expressions for real-life situations, such as finding the sum of two numbers or the difference between two values. Boost your algebra skills and become a pro at handling variables!

## Want to join the conversation?

- What do you put when it says "what is the quotient of 9 and c?"(28 votes)
- Quotient means division. This is asking you for the division of 9 and c. Does that help?(52 votes)

- what does increased by mean? Is it multipilying or what?(7 votes)
- It means addition

If you have 3 apples and I give you 2 more, then your number of apples has increased by 2.

3 + 2 = 5

You now have 5 apples.

Hope this helps.(22 votes)

- ok so i got a question, 8 increased by g. Simple right? Just supposed to write that in an expression. Same as you would say m decreased by 2 is m-2. But what is 8 increased by g? Just simple adding 8+g?(10 votes)
- Yes. 8 + g. Everything you can do with a number (add, subtract, multiply, divide, exponentiate, etc.) you can do with a variable. It's just a number with a different name.(10 votes)

- Seven multiplied by x can be written as 7x. Can it also be written as x7, since multiplication is commutative?(6 votes)
- Yeah, nick is right. It's not incorrect, but it's going to turn heads. You'll eventually run into a teacher who won't accept it.(6 votes)

- This video is kind of helpful, but I still don't really get it. On one of the questions, it said, 10-3 times 2. I answered 14 because it was 10-3 is seven, then times 2, it would equal 14. But is was 4. How the heck could it be 4.(4 votes)
- You need to follow order of operations rules (PEMDAS). You can't start with subtraction. You need to multiply, then subtract

10-3(2) = 10-6 = 4

Hope this helps.(13 votes)

- how is this so post to help me with Algerbraic Expressions??(6 votes)
**so...actually using variables and stuff can help in future problems of algebra like finding the whole sum of variable and things**(7 votes)

- I wonder if Sal ever gets his math answers wrong.(4 votes)
- Everyone makes errors, even Sal. You will see videos that have correct boxes to fix errors that he made in the original vide.(9 votes)

- is it possible to put the variables before the number in the equation when using multiplication.(5 votes)
- When using multiplication, it is possible.

You can write`5x`

as`x5`

because the commutative property of multiplication tells us that these are the same / equal. But, it is generally not written that way. It is much easier to read with the numbers in front of the variable.(6 votes)

- Write an expression for "the product of 11 and w."What about this one ?(4 votes)
- dose it mater what order it is in(2 votes)

- Wouldn't it be commutative?(6 votes)

## Video transcript

- [Voiceover] Let's do some examples of the writing expressions
with variables exercise. So it says "Write an expression to represent 11 more than a." Well you could just have a but if you want 11 more than a, you would wanna add 11 so you could write that as a plus 11. You could also write that as 11 plus a. Both of them would be 11 more than a. So let's check our answer here. We got it right. Let's do a few more of these. "Write an expression to represent the sum of d and 9." So the sum of d and 9, that means you're gonna add d and 9. So I could write that as d plus 9 or I could write that as 9 plus d. And check our answer. Got that right. Let's do a few more of these. "Write an expression to
represent j minus 15." Well, I could just write
it with math symbols instead of writing the word minus. Instead of writing M-I-N-U-S, I could write j minus 15. And then I check my answer. Got it right. Let's do a few more of these. This is a lot of fun. "Write an expression to
represent 7 times r." There's a couple ways I could do it. I could use this little
dot right over here, do 7 times r like that. That would be correct. I could literally just write 7r. If I just wrote 7r that would also count. Let me check my answer. That's right. Let me do a couple of other of these just so you can see that I could've just done 10 and this is not a decimal, it sits a little bit
higher than a decimal. It's multiplication and the reason why once you start doing
algebra, you use this symbol instead of that kind of
cross for multiplication is that x-looking thing
gets confused with x when you're using x as a variable so that's why this is a lot more useful. So we wanna write 10 times u, 10 times u, let's check our answer. We got it right. Let's do one more. "Write an expression to
represent 8 divided by d." So we could write it as
8 and then I could write a slash like that, 8 divided by d. And there you go. This is 8 divided by d. Let me check, let me check the answer. I'll do one more of these. Oh, it's 6 divided by b. Alright, same thing. So 6, I could use this
tool right over here. It does the same thing as if I were to press the backslash. So 6 divided by b. Check my answer. We got it right.