Algebra 1 Common Core Student Edition, Grade 8-9

W h a t if an ite m is in
both sets?
Sets L and R each contain
a quarter, so a quarter
is in the union of L and
R. You should list it only
once, though.

Uni on of Set s

I n y o u r l e f t p o c k e t , y o u h a v e a q u a r t e r , a p a p e r c l ip , a n d a k e y. I n y o u r r i g h t p o c k e t ,

y o u h a v e a p e n n y , a q u a r t e r , a p e n c i l , a n d a m a r b le. W h a t is a s e t t h a t r e p r e s e n t s t h e

d i f f e r e n t i t e m s i n y o u r p o c k e ts?

Write sets that represent the contents of each pocket.

L e f t p o c k e t : L = {quarter, paper clip, key}

Right pocket: R = {p e n n y, quarter, pencil, m a rb le }

W r it e t h e u n i o n o f t h e sets, w h ic h r e p r e s e n ts t h e d i f f e r e n t it e m s t h a t a re i n

your pockets.

L U R = {quarter, paper clip, key, penny, pencil, m arble}

1. a. Write sets P a n d Q b e lo w i n r o s t e r f o r m. W h a t is P U Q1
   P = { x | x is a w h o le n u m b e r le s s t h a n 5 }
   Q = {y | y is a n e v e n n a t u r a l n u m b e r le s s t h a n 5 }
   0 b. Reasoning W h a t is t r u e a b o u t t h e u n i o n o f t w o d i s t i n c t s e ts i f o n e s e t is
   a s u b s e t o f th e o th e r?

The intersection o f t w o o r m o r e se ts is t h e s e t o f e le m e n ts t h a t a re c o m m o n t o e v e r y

se t. A n e le m e n t is i n t h e in t e r s e c t io n i f i t b e lo n g s t o all o f th e sets. T h e s y m b o l f o r

in t e r s e c t io n is D. W h e n y o u f i n d t h e in t e r s e c t io n o f t w o sets, l i s t o n l y th e e le m e n ts t h a t

a re i n b o t h sets. I n t h e V e n n d ia g r a m b e lo w , A fT B is shaded.

U

Disjoint sets have no elem ents in com m on. The intersection o f d isjo in t sets is the

e m p t y set. T h e d ia g r a m b e lo w s h o w s t w o d i s jo in t sets.

U

A and B

are disjoint.