Algebraic expressions are useful because they represent the value of an expression for all of the values a variable can take on.

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

"two more than five"

can be written as the expression

$5+2$.

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

Bijvoorbeeld,

"three 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.

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

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

"the product of eight and $k$"

can be written as

$8k$.

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

So, the expression is $m - 7$.