1. PRE-ALGEBRA

2. Lesson 1-3 Warm-Up

3. PRE-ALGEBRA To evaluate an algebraic expression, replace the varaibles (letters) with the numbers they equal and solve using PEMDAS. Writing and Evaluating Expressions (1-3) How do you evaluate an algebraic expression? Example: Evaluate 4y - 15 for y = 9 4 (9) - 15Step 1: Replace the variable with the number equals. 36 - 15Step 2: Solve using order of operations [PEMDAS] 21 Example: Evaluate 3ab + c /2 for a =2, b = 5, and c = 10 3(2)(5) + 10 / 2 Step 1: Replace the variable with the number it equals. 30 + 5 Step 2: Solve using order of operations [PEMDAS] 35

4. PRE-ALGEBRA Evaluate 18 + 2g for g = 3. 18 + 2g = 18 + 2(3)Replace g with 3. = 18 + 6Multiply. = 24Add. Writing and Evaluating Expressions LESSON 1-3 Additional Example

5. PRE-ALGEBRA Evaluate 2ab – for a = 3, b = 4, and c = 9. = 24 – 3Multiply and divide from left to right. = 21 Subtract c3c3 2ab – = 2(3)(4) –Replace the variables. c3c3 (9) 3 Writing and Evaluating Expressions LESSON 1-3 Additional Example

6. PRE-ALGEBRA Example: An online store charges $14 for each CD and $6 per order. How much would it cost to order 8 CDs? Number of CD s Cost of CD s Shipping Total Cost 1 1 x 14 6 1 x 14 + 6 = 14 + 6 = 20 2 2 x 14 62 x 14 + 6 = 28 + 6 = 34 4 4 x 14 64 x 14 + 6 = 56 + 6 = 62 8 8 x 14 68 x 14 + 6 = 112 + 6 = 118 Step 1: Create a table to find the pattern (see above). n x 14 + 6Step 2: Write an expression using the pattern (8) x 14 + 6Step 3: Replace the variable with the number it equals 112 + 6Step 4: Solve using order of operations [PEMDAS] 118 Writing and Evaluating Expressions (1-3)

7. PRE-ALGEBRA The Omelet Café buys cases of 36 oranges. a.Write an algebraic expression for the number of cases the Café should buy for x oranges. b.Evaluate the expression for 180 oranges. a. x oranges b. 180 oranges x 36 = Evaluate for x = 180. (180) 36 x 36 = 5Divide. The Omelet Café should buy 5 cases to get 180 oranges. Writing and Evaluating Expressions LESSON 1-3 Additional Example

8. PRE-ALGEBRA The One Pizza restaurant makes only one kind of pizza, which costs $16. The delivery charge is $2 per delivery. Write an algebraic expression for the cost of having pizzas delivered. Evaluate the expression to find the cost of having two pizzas delivered. $2 delivery charge = number of pizzas. Words for each Let $16 p pizzaplus Evaluate the expression for p = 2. 16 p + 2 = 16 (2) + 2 = 32 + 2 = 34 It costs $34 to have two pizzas delivered. Expression 16 p2+ Writing and Evaluating Expressions LESSON 1-3 Additional Example

9. PRE-ALGEBRA Evaluate. 1.7(b) – 4 for b = 3 2.h ÷ 2 + 1 for h = 12 3.3c + 4 ÷ d for c = 8, d = 24.fg – g for f = 5, g = 7 5. Pens are sold at the school store in packages of 4. Write an algebraic expression for the number of packages a student should buy to get p pens. Evaluate this expression for 12 pens. 26 177 28 12 4 p 4 = 3 packages ; Writing and Evaluating Expressions LESSON 1-3 Lesson Quiz