Warm-ups!Every lamb has 4 legs. Every chicken has 2

legs.• 1. How many legs do 5 lambs and 20

chickens have?

• 2. How many legs do 100 lambs and 27 chickens have?

• 3. How many legs do L lambs and C chickens have?

60 legs

454 legs

4l + 2c

Describing Patterns

Section 1.2

Objectives for the day:• Use variables to describe patterns in

instances or tables• Identify and apply the associative,

commutative, and transitive properties

• Create expression to model real-world situations.

Definitions• Term:

• Factor:

• Instance:

• Pattern:A group of terms which a connection or relationship can be found

One term of a pattern

A number, variable, or combination of the two

A number of expression that is multiplied.*If a ∙ b = c, then a and b are factors of c.

Ex. 5x2 + 7x + 8y + 6 has 4 terms

Evaluate each expression #1 - 3

2(3 + 8) ÷ 3

2(4 + 8) ÷ 3

2(5 + 8) ÷ 3

Write another instance of the pattern (#4):2 ( 9 + 8) ÷ 3

22/3

8

26/3

Give two instances of each pattern

# 5: # 6:4 x3 = 4 x x x ∙ ∙ ∙4 (2)3 = 4 2 2 2∙ ∙ ∙4(-3)3 = 4 -3 -3 -3∙ ∙ ∙

Use the commutative property of multiplication to find another expression that gives the same value as 6a b ∙

b 6a∙

7 (4 + 3) = 7 ∙ 4 + 21

7 (11 + 3) = 7 ∙ 11 + 21

7 (x + 3) = 7 ∙ x + 21

Three instances of a pattern are given. Describe the pattern using one variable.3 1 – 7 = 3 (1 – 4) + 5∙3 11 – 7 = 3 (11 – 4) + 5∙3 ¼ – 7 = 3 (¼ – 4) + 5∙

3 ∙ x – 7 = 3 (x – 4) + 5

Example 2Jana designs and sells t-shirts online. She

works through a company that pays her a base of $50 every month for her designs, plus a 20% profit for every t-shirt that is sold. Each shirt costs $20.

#9: write an expression that calculates Jana’s monthly earnings if she sells s t-shirts.

#10: How much does Jana make in a month when she sells 30 t-shirts?

50 + .2(20s) dollars

50 + .2(20 ∙ 30) dollars $170.00

Break up into groups of 4:

Homework

Finish worksheet 1.2APages 16 – 17

1 – 22 (ex. Cred: 23)