Algebra 1 Common Core Student Edition, Grade 8-9

Activities

Fif t y students were polled about t heir aft er- scho o l act ivit ies. All said

that they participate in one or more of three clubs: the Robotics Club

(RC), t he St udent Council (SC), and t he Th eat er Club (TC). How many

st u d en t s p ar t i ci p at e in t h e t h e at e r club o nly? Use t h e in f o rm at io n in

t he t ab le. Explain your reasoning.

Unions and

Intersections o f Sets

Co m m o n Co r e St at e St a n d a r d s

A-CED.A.1 Create equations and inequalities in one

variable and use them to solve p ro b le m s...

M P 1, MP 2, MP 3, MP 4

Object ive T o f i n d t h e u n io n s a n d in t e r s e c t io n s o f sets

Getting Ready!

What is the

meaning o f the

middle area where

th e th re e circles

overlap?

MATHEMATICAL

1 PRACTICES

Lesso n

Vocabulary

• union


• intersection


• disjoint sets

C e r t a in r e g io n s o f th e V e n n d ia g r a m i n t h e S o lv e I t s h o w unions a n d intersections

of sets.

Essent ial Und er st and ing Given two or more sets, you can describe which

e le m e n ts b e lo n g t o at least one s et. Y o u c a n a ls o d e s c r ib e w h ic h e le m e n ts b e lo n g t o all

o f t h e sets. Y o u u s e s y m b o ls t o r e p r e s e n t th e s e r e la t io n s h ip s.

The union o f t w o o r m o r e sets is t h e s e t t h a t c o n t a in s a ll e le m e n ts o f th e sets. T h e

s y m b o l f o r u n i o n is U. T o f i n d th e u n i o n o f t w o sets, l i s t t h e e le m e n ts t h a t a re i n e it h e r

set, o r i n b o t h sets. A n e le m e n t is i n th e u n i o n i f i t b e lo n g s t o at least one o f th e sets. I n

th e V e n n d ia g r a m b e lo w , A U B is shaded.

AUfi

214 Chapter 3 Solving Inequalities