Algebraic Expressions

Writing Algebraic Expressions

 

Problem:   Ms. Jensen likes to divide her class into groups of 2. Use mathematical symbols to represent all the students in her class.  [IMAGE]
Solution:   Let g represent the number of groups in Ms. Jensen's class.
  Then 2 · g, or 2g can represent "g groups of 2 students".

In the problem above, the variable g represents the number of groups in Ms. Jensen's class. A variable is a symbol used to represent a number in an expression or an equation. The value of this number can vary (change). Let's look at an example in which we use a variable.

Example 1:     Write each phrase as a mathematical expression.

 
Phrase Expression
the sum of nine and eight 9 + 8
the sum of nine and a number x 9 + x

The expression 9 + 8 represents a single number (17). This expression is a numerical expression, (also called an arithmetic expression). The expression 9 + x represents a value that can change. If x is 2, then the expression 9 + x has a value of 11. If x is 6, then the expression has a value of 15. So 9 + x is an algebraic expression. In the next few examples, we will be working solely with algebraic expressions.

From: http://www.mathgoodies.com/lessons/vol7/expressions.html