1. Ch 1.3 – Order of Operations
Objective:
To simplify expressions using the order of operations.

2. Order of Operations (PEMDAS)
The Order of Operations are rules that explain how to evaluate mathematical expressions.
Parenthesis
Exponents
Multiplication & Division
Addition & Subtraction

3. Example = 2 + 3 * 4 = 5 * 4 = 20 = 2 + 12 = 14 This is WRONG!
This is CORRECT!
1 * * 4
= * 4
= * 4
= 20
Multiply – Add – Multiply NO!
1 * * 4 = =
Multiply – Multiply - Add YES!

4. Order of Operations Parenthesis Exponents Multiply / Divide
1) 6 + 5(8 - 2)
6 + 5(6)
= 36
Exponents 2)
= 77
Multiply / Divide 3)
= 32
Add / Subtract 4)
7 + 8 = 15

5. Try These
Simplify each expression below.
1) 6 + 5(8 - 2) 2) 3) 4)

6. Simplify the following.1) 3)
(4 + 18)2 - 10
(22)2 - 10
-1 + 5
= 34 4 2) 4)
24 - 2[ ]
8 + 20
24 - 2[3] 4
= 18 28 = 7 4

7. Evaluate the expression if a = 2, b = 4, and c = 8
1) ab - c 3) 2
(2)(4) - 8
4 + 3(2)
8 - 8
4 + 3(4) 2
= 10
2) 3a(c - b) 4)
3(2)(8 - 4)
2(4 + 8)
3(2)(4) 2
2(12) 24 24 =
= 12 2 2

8. Fact: Scientific calculators and computers follow the order of operations. Basic calculators do not.
3 + 4 x 2 =
3 + 4 x 2 = = *
7 x 2 = 14
3 + 8 = 11
3 + 8 = 11

9. Symbolic Differences in Calculators and Computers
Scientific
Calculator
Expression
Computer + + + - - - x x * /
4 ^ 2 4 2
4 x 2 y

10. Key Sequences and Computer Input
Calculator
Key Sequence
Expression
Computer
3(8 - 2)
4 3
6 - 2
6 + 8 2
3 - 1