Chapter 1 Review In Algebra, we use symbols to stand for various numbers. One type of symbol used is a variable. An expression that contains at least one variable is called an algebraic expression. We can replace a variable with a number; this is called substituting for the variable. To evaluate an algebraic expression, substitute a number for each variable and calculate.

Definitions continued… Natural numbers are the numbers used for counting. Whole numbers are the natural numbers and zero. Parenthesis are grouping symbols. Order of Operations: PEMDAS

Properties Commutative Properties Addition: a+b = b+a Multiplication: ab=ba (these are equivalent expressions). Identity Properties Addition: a+ 0 = a, 0+a = a Multiplication: 1*a = a, a*1 = a

More defs When two numbers are multiplied to form a product, each number is called a factor. The process of finding the simplest form is called simplifying. Whenever two algebraic expressions are equivalent, we can substitute one for the other. A product in which the factors are the same is called a power. Exponent/base: When an expression is written with exponents, we say the expression is written using exponential notation.

Associative/Distributive Properties Associative Property of Addition a+(b+c) = (a+b)+c Associative property of Multiplication a* (b*c) = (a*b)*c Distributive property of Multiplication a(b+c) = ab+ac (b+c)a = ba +ca

Do you know these defs? In an expression like 6s+6t+6w, what are the terms? Terms such as 5x and 4x, whose variable factors are exactly the same are called: