Why do you talk in this ducument that 3 more than x is x+3? It should be3+x

Because of the commutative property of addition "x+3" and "3+x" mean exactly the same thing. Both are acceptable translations of the phrase.

I have a weird problem, when I practiced on khan on subtraction with algebra it showed something like this p - 6 I use that example to do my subtraction problem on IXL but it said it was wrong I had to put the number then the letter.

"p - 6" and "-6 + p" are equivalent and it shouldn't matter which term comes first. The commutative property of addition tells use the 2 expressions are identical. However, you may have been given some explicit directions in IXL that asked you to write the terms in a certain order. If you didn't follow their instructions, that could have caused it to be wrong. The other possibility is that you confused "p - 6" with "-6p". The first one is subtraction. The second one is multiplication. These are different. Hope this helps.

Main content

Course: Algebra (all content) > Unit 1

Lesson 5: Writing algebraic expressions introduction

Writing expressions

Google Classroom

Learn to write algebraic expressions in and out of word problems.

Why do we have math if we can describe things in words?

Sometimes in math we describe an expression with a phrase. For example, the phrase

" $2$ ‍ more than $5$ ‍"

can be written as the expression

$2 + 5$ ‍.

Similarly, when we describe an expression in words that includes a variable, we're describing an algebraic expression (an expression with a variable).

For example,

" $3$ ‍ more than $x$ ‍"

can be written as the algebraic expression

$x + 3$ ‍.

But why? Why use math if we can describe things in words? One of the many reasons is that math is more precise and easier to work with than words are. This is a question you should keep thinking about as we dig deeper into algebra.

Different words for addition, subtraction, multiplication, and division

Here is a table that summarizes common words for each operation:

Operation	Words	Example algebraic expression
Addition	plus, sum, more than, increased by	$x + 3$ ‍
Subtraction	subtracted, minus, difference, less than, decreased by	$p - 6$ ‍
Multiplication	times, product	$8 k$ ‍
Division	divided, quotient	$a \div 9$ ‍

For example, the word "product" tells us to use multiplication. So, the phrase

"the product of $8$ ‍ and $k$ ‍"

can be written as

$8 k$ ‍.

Let's take a look at a trickier example

Write an expression for " $m$ ‍ decreased by $7$ ‍".

Notice that the phrase "decreased by" tells us to use subtraction.

So the expression is

m - 7

Let's try some practice problems!

Basic expressions

Write an expression for " $y$ ‍ more than $7$ ‍".

Write an expression for " $6$ ‍ minus $b$ ‍".

Write an expression for " $x$ ‍ divided by $9$ ‍".

Write an expression for " $2$ ‍ multiplied by $t$ ‍".

Write an expression for "the sum of $a$ ‍ and $4$ ‍".

More complicated expressions

Write an expression for " $8$ ‍ less than the product of $7$ ‍ and $x$ ‍".

Write an expression for "the sum of $6$ ‍ and the product of $3$ ‍ and $d$ ‍".

Word problems

Daniel makes

100

dollars each week. He worked for

x

weeks this summer.

How much money did Daniel make this summer?
Write your answer as an expression.

Number of weeks	Money Daniel made
$1$ ‍	$100 \cdot 1 = 100$ ‍
$2$ ‍	$100 \cdot 2 = 200$ ‍
$3$ ‍	$100 \cdot 3 = 300$ ‍
$x$ ‍	$100 \cdot x = 100 x$ ‍

Sebastian has

12

more trophies than Megan. Megan has

t

trophies.

How many trophies does Sebastian have?
Write your answer as an expression.

Let's see what happens as the amount of trophies Megan has increases:

Megan's trophy count	Sebastian's trophy count
$10$ ‍	$10 + 12 = 22$ ‍
$20$ ‍	$20 + 12 = 32$ ‍
$30$ ‍	$30 + 12 = 42$ ‍
$t$ ‍	$t + 12$ ‍

The answer: $t + 12$ ‍

Want to join the conversation?

Sort by:

David Bacon
Posted 7 years ago. Direct link to David Bacon's post “I have a problem with sen...”
I have a problem with sentence problem like this:Write an expression for "
8
less than the product of
7
and
x
". and I wrote 8-7x but they gave me wrong how I can answer that ?
Button navigates to signup pageComment on David Bacon's post “I have a problem with sen...”
(7 votes)
Answer
- spriha
  Posted 7 years ago. Direct link to spriha's post “because it says "8 less t...”
  because it says "8 less than", that means that 8 is supposed to be subtracted from whatever part of the expression is after it, so the answer would be 7x-8. i hope this helped. :)
  Comment on spriha's post “because it says "8 less t...”
  (17 votes)
jennifer
Posted 8 years ago. Direct link to jennifer's post “Why do you talk in this d...”
Why do you talk in this ducument that 3 more than x is x+3? It should be3+x
Button navigates to signup pageComment on jennifer's post “Why do you talk in this d...”
(1 vote)
Answer
- Kim Seidel
  Posted 8 years ago. Direct link to Kim Seidel's post “Because of the commutativ...”
  Because of the commutative property of addition "x+3" and "3+x" mean exactly the same thing. Both are acceptable translations of the phrase.
  Button navigates to signup page
  (3 votes)
sicspi
Posted 3 years ago. Direct link to sicspi's post “How do I solve this probl...”
How do I solve this problem 8 squared
Button navigates to signup pageButton navigates to signup page
(2 votes)
Answer
asgal
Posted 5 years ago. Direct link to asgal's post “I have a weird problem, w...”
I have a weird problem, when I practiced on khan on subtraction with algebra it showed something like this p - 6 I use that example to do my subtraction problem on IXL but it said it was wrong I had to put the number then the letter.
Button navigates to signup pageButton navigates to signup page
(1 vote)
Answer
- Kim Seidel
  Posted 5 years ago. Direct link to Kim Seidel's post “"p - 6" and "-6 + p" are ...”
  "p - 6" and "-6 + p" are equivalent and it shouldn't matter which term comes first. The commutative property of addition tells use the 2 expressions are identical. However, you may have been given some explicit directions in IXL that asked you to write the terms in a certain order. If you didn't follow their instructions, that could have caused it to be wrong.
  
  The other possibility is that you confused "p - 6" with "-6p". The first one is subtraction. The second one is multiplication. These are different.
  
  Hope this helps.
  Comment on Kim Seidel's post “"p - 6" and "-6 + p" are ...”
  (2 votes)
fatimakassim287
Posted 7 years ago. Direct link to fatimakassim287's post “These were some pretty ea...”
These were some pretty easy questions. The problem is that its very confusing for which order I should put the problem in.
Button navigates to signup pageButton navigates to signup page
(1 vote)
Answer
kharris
Posted 7 years ago. Direct link to kharris's post “What is this? Is this in ...”
What is this? Is this in High School. I've got 3 years till High School
Button navigates to signup pageButton navigates to signup page
(1 vote)
Answer
- Ryan Whitsett
  Posted 7 years ago. Direct link to Ryan Whitsett's post “But this is just the easy...”
  But this is just the easy part of algebra 1
  Button navigates to signup page
  (1 vote)
Mmesoma Nwabuwa
Posted 6 years ago. Direct link to Mmesoma Nwabuwa's post “This stuff is pretty easy...”
This stuff is pretty easy but i can never be too sure. That is why i'm going back to the basics of it to learn it again and improve my skills
Button navigates to signup pageButton navigates to signup page
(1 vote)
Answer
ayae
Posted 7 years ago. Direct link to ayae's post “I'ts pretty easy once you...”
I'ts pretty easy once you you learn the system and the patterns that were put into the problems.
Button navigates to signup pageComment on ayae's post “I'ts pretty easy once you...”
(1 vote)
Answer
Sarah dream
Posted 6 years ago. Direct link to Sarah dream's post “anyone know what m decrea...”
anyone know what m decreased by 200 is?
Button navigates to signup pageButton navigates to signup page
(1 vote)
Answer
VIOLET9364
Posted 4 years ago. Direct link to VIOLET9364's post “At 6:38 what is the answe...”
At
6:38
what is the answer to 51 less than x squared?
Button navigates to signup pageButton navigates to signup page
(1 vote)
Answer