Symbols and Expressions 1 1 I Algebraic Expressions

Symbols and Expressions 1 -1

I. Algebraic Expressions Vocabulary: 1. Variable – letter that represents one or more numbers 2. Algebraic expression – an expression that contains at least 1 variable 3. Evaluate – substituting a number for each variable and calculate 4. Natural numbers – numbers used for counting (1, 2, 3, and so on) 5. Whole numbers – natural numbers and zero (0, 1, 2, and so on) 6. Rational numbers – set of numbers that include natural and whole numbers

II. Order of Operations The order in which we solve all math expressions Please - Parentheses (and all other grouping symbols) Excuse - Exponents My Dear - Multiplication, Division (left to right) Aunt Sally - Addition, Subtraction (left to right)

7 2 + [7 + 3(5 – 2)] ÷ 4 2 7 2 + [7 + 3(3)] ÷ 4 2 7 2 + [7 + 9] ÷ 4 2 7 2 + 16 ÷ 4 2 14 + 8 22

Examples: 1. 36 ÷ (4 + 5) 2. 24 – (12 + 3) ÷ 5 3. 4 + 6 2 1

III. Evaluating Substitute the given number for the variables listed You cannot evaluate without being given the value Once you substitute the values into the problem, solve using the order of operations t + 3 + t for t = 4 4+3+4 7+4 11

Examples: 1. 14 – (b + 5) for b = 3 2. s(t – 4) for s = 4, t = 8 3. x + 5 2 3 for x = 7