Main content

## 6th grade

### 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

© 2023 Khan AcademyTerms of usePrivacy PolicyCookie Notice

# Writing expressions with variables

To write simple algebraic expressions from mathematical statements, you can follow this procedure: 1. Identify the key terms in the written statement (e.g. "sum," "product," "quantity"). 2. Break the statement down into its component parts. 3. Translate each part into algebraic form, using the appropriate symbols and operations.
4. Simplify the expression if needed. Created by Sal Khan.

## Want to join the conversation?

- whats a quanity(46 votes)
- Exactly.It can be a negative number to infinity,a positive number to infinity and zero.In fact, ANY number is a quantity.(24 votes)

- When there's a problem with division, how do you know what's the numerator and what's the denominator?(10 votes)
- Here the number above the fraction bar is the numerator, and the one below the fraction bar is the denominator. A numerator represents the number of parts out of the whole, which is the denominator. did that help(6 votes)

- i just need 25 upvotes(21 votes)
- What is a quotient?(9 votes)
- Quotient is the result of division.

So, if you are asked to "find the quotient of a number and 6" you would do "x/6".

Hope this helps.(17 votes)

- Why does it change from 1x to x(6 votes)
- "1x" and "x" mean the same thing. It is common practice to not write in the coefficient of 1.(4 votes)

- When there's a problem with total, what do you do?(4 votes)
- save the planet I guess 😂(1 vote)

- When it says, "Eight less than the product of 2 and the letter x" how do you know if you have to put the -8 before or after the 2x?(5 votes)
- The problem says eight
*less than*, which suggests subtraction is needed. Subtraction, unlike addition, is not communative, meaning 3-4 will not equal 4-3 (but for addition 3+4 will equal 4+3), so since it's 8 less than 2x it will be 2x - 8. Hope I helped, let me know if there's anything you need to clarify :)(3 votes)

- I have a question to this problem:

A zoo has two fewer elephants than zebras and five times more monkeys than elephants. The total number of elephants, monkeys, and zebras is 30.

The expression is z + (z-2) + 5(z-2) = 30.

I dont know why for the part where it says "five times more monkeys than elephants," i do know that five times is distributive property but i dont know why its z-2 when it says five times more monkey than elephants.

Im sorry for asking you this i just need help on this with my homework. Thank you.(2 votes)- In your equation, z=number of zebras.

There are 2 fewer elephants than zebras gives you that elephants = z-2

5 times more monkeys than elephants means the number of monkeys is 5 (number of elephants) = 5(z-2)

Hope this helps.(3 votes)

- This is some what hard to Lear but I get it a little bit(3 votes)
- What is the difference between the wording of 'less' and 'minus' in describing an expression with variables?(1 vote)
- "Less" and "minus" mean the same thing in word problems. For example, "ten less two times x" would be written as 10-2x, and "ten minus two times x" would be written as 10-2x. However, when you see the words "less than," you have to be careful. Although "less" means the same as "minus," "less than" essentially means to do subtraction in reverse – i.e. "ten less than two times x" would be written as 2x-10,
*not*10-2x.(5 votes)

## Video transcript

What I want to do
in this video is write the algebraic expressions
that represent the same thing that these statements
are saying. So this first statement, they
say the sum of negative 7 and the quantity 8 times x. So the sum-- so we're going
to have an addition here-- of negative 7 and the
quantity 8 times x. So the quantity 8 times
x, well, that's just 8x. So I can just write
8x over there. So it is negative 7 plus 8x. Or you could view this
as the sum of negative 7 and the quantity 8 times x. Let's do the next one. Take the quantity negative
3 times x and then add 1. So the quantity
negative 3 times x, we can write that
as negative 3x. And then we need
to add 1 to that. So that's going to be plus 1. Now this one. Negative 6 plus--
so we can write negative 6 plus something-- the
product of negative 1 and x. So the product of
negative 1 and x, that's just going to
be negative 1x, which is the same thing as negative x. So we can write this as
negative 6 plus negative x. Or we can just
write this-- this is the exact same thing
as negative 6 minus x. And we are done.