Lesson 4 Chapter 1

Objectives Translate word phrases involving numerical relationships into mathematical expressions

Vocabulary Formulas Area of a rectangle: A = lw Perimeter of a rectangle: P = 2l + 2w Distance Traveled: D= rt Cost: C = np

Key Concept PhraseTranslation AdditionThe sum of 8 and x A number increased by 7 5 more than a number 8 + x n + 7 n + 5 SubtractionThe difference between a number and 4 A number decreased by 8 5 less than a number 6 minus a number x – 4 x – 8 n – 5 6- n Multiplicatio n The product of 4 and a number Seven times a number One third of a number 4n 7n 1/3 n DivisionThe quotient of a number and 8 A number divided by 10 n/8 n/10

Example 1 Translate each phrase into a variable expression. a) 3 less than half of x ½ x – 3 b) Half the difference between x and 3 ½(x – 3)

Example 2 Find the area and perimeter of a rectangle with a length of 10 and a width w. Area = length x widthPerimeter = (2 x length) + (2 x width) A = 10 ∙ wP= (2 ∙ 10) + (2 ∙ w) A = 10wP= w

Example 3 You and your friends buy 2 pizzas at p dollars each and 4 salads at s dollars each. How much do you and your friends spend? Cost = number x price Pizza cost = 2pSalad cost = 4s Total cost = 2p + 4s

Example 4 You travel (h + ½) hours at 80 km/h. How far do you travel? Distance = rate x time = 80 (h + ½) You travel 80(h + ½) km.

Guided Practice 1. Four times a number 2. One half of a number 3. Eight more than twice a number 4. Six less than a number

Homework Pg ; 1-41 (odd) and (even)

When you finish you may: 1) Get on Randolph.net site to check HW or… 2) Use links from my math wiki to get on Khan Academy or Class Zone.