# Parts of An Expression

An algebraic expression is a collection of terms that are separated by addition and/or subtraction. Terms can be:

•a constant (number by itself) 12

•a variable ( a letter than represents a number) x

•the product of a number and a variable 4y

•the product of two variables xy

•or the product of a constant and more than one variable 3ab2c

Example 1:

4x + 9y - 4

The terms are: 4x, 9y, and -4

The constant is: -4

Example 2:

3x2y - 2xy + xy2

The terms are:3x2y, - 2xy, xy2

The constant is: there is no constant

A coefficient is the number that is being multiplied by a variable. Let's look at a couple of examples:
• -3x the coefficient is -3
• 2 x2ythe coefficient is 2
• -xy the coefficient is -1
• abc the coefficient is the "understood" 1

Sum it up: An algebraic expression is a group of terms that is separated by addition and/or subtraction. Terms are formed by a constant, a variable, or a product of constants and variables. The coefficient is the number that is being multiplied by a variable.

 Related Links: Math algebra Positive and Negative Integer Exponents Rational (Fractional) Exponents

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