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Amy Ferguson Moncure

Geometry · Unit 1

Compound Statements

Join propositions with AND, OR, and NOT, and say a symbolic sentence in words.

Jump to section:

∧ AND   ∨ OR   ∼ NOT

What to Remember

Proposition

A proposition is a sentence that is true or false. “A triangle has 3 sides” is a proposition. “Draw a triangle” is not.

Conjunction ∧ AND

p ∧ q is true only when both parts are true.

Disjunction ∨ OR

p ∨ q is true when at least one part is true.

Negation ∼

∼p is the opposite of p. Parentheses first, then negation, then ∧ and ∨.

Level 1

Easy

Name the connective, then say the compound sentence in words.

Example
p: Maya packed a sweater. q: Maya packed boots. Write p ∧ q in words.

p ∧ q means both parts are true.

Maya packed a sweater and Maya packed boots.

Answer: Maya packed a sweater and Maya packed boots.

1
p: The light is on. q: The door is locked. Write p ∨ q in words.
Show Answer

p ∨ q means at least one part is true.

The light is on or the door is locked.

Answer: The light is on or the door is locked.

2
p: The polygon is regular. Write ∼p in words.
Show Answer

∼p is the opposite of p.

The polygon is not regular.

Answer: The polygon is not regular.

3
Which connective is AND?
Show Answer

∧ is conjunction (AND).

∨ is disjunction (OR).

Answer: ∧

4
p: Angle A is acute. q: Angle B is obtuse. Write p ∧ q in words.
Show Answer

p ∧ q

Angle A is acute and angle B is obtuse.

Answer: Angle A is acute and angle B is obtuse.

5
p: AB is parallel to CD. Write ∼p in words.
Show Answer

∼p

AB is not parallel to CD.

Answer: AB is not parallel to CD.

Level 2

Medium

Parentheses. Translate a compound proposition with three parts.

Example
Use these propositions.

p: The trail is open.

q: It is raining.

r: We pack rain jackets.

Write (p ∨ q) ∧ r in words.

(p ∨ q) ∧ r

The whole statement is true when r is true, and at least one of p or q is true.

The trail is open or it is raining, and we pack rain jackets.

Answer: The trail is open or it is raining, and we pack rain jackets.

1
p: Nia takes the bus. q: Nia walks. r: Nia brings a lunch. Write p ∧ (q ∨ r) in words.
Show Answer

p ∧ (q ∨ r)

Nia takes the bus, and Nia walks or Nia brings a lunch.

Answer: Nia takes the bus, and Nia walks or Nia brings a lunch.

2
p: The figure is a square. q: The figure is a rhombus. Write ∼(p ∧ q) in words.
Show Answer

∼(p ∧ q)

It is false that the figure is a square and a rhombus.

Answer: It is false that the figure is a square and a rhombus.

3
p: It is Friday. q: The lab is due. Write ∼p ∨ q in words.
Show Answer

∼p ∨ q

It is not Friday, or the lab is due.

Answer: It is not Friday, or the lab is due.

4
For the whole statement (p ∨ q) ∧ r to be true, which parts must be true?
Show Answer

The AND is outside, so r must be true.

At least one of p or q must be true.

Answer: r, and at least one of p or q

5
p: The kettle is on. q: The tea is ready. Write ∼p ∧ ∼q in words.
Show Answer

∼p ∧ ∼q

The kettle is not on and the tea is not ready.

Answer: The kettle is not on and the tea is not ready.

Level 3

Hard

Match a sentence to symbols, or write a symbolic sentence in words.

Example
p: The soup is hot. q: The bread is ready. Write p ∧ ∼q in words.

p ∧ ∼q

The soup is hot and the bread is not ready.

Answer: The soup is hot and the bread is not ready.

1
p: The oven is on. q: The timer is set. r: The bread is baking. Which expression matches “The oven is on or the timer is set, and the bread is baking”?
A. p ∨ (q ∧ r)
B. (p ∨ q) ∧ r
C. p ∧ q ∧ r
D. p ∨ q ∨ r
Show Answer

“Or” joins oven and timer inside parentheses.

AND the bread is baking sits outside.

(p ∨ q) ∧ r

Answer: B

2
p: It is raining. q: We walk. r: We bike. Which expression matches “It is not raining, and we walk or we bike”?
A. ∼p ∧ (q ∨ r)
B. ∼(p ∧ (q ∨ r))
C. (∼p ∧ q) ∨ r
D. ∼p ∨ q ∨ r
Show Answer

NOT raining is outside the OR.

Walk or bike stays in parentheses.

∼p ∧ (q ∨ r)

Answer: A

3
p: The battery is charged. q: The tablet turns on. Write ∼(p ∨ q) in words.
Show Answer

∼(p ∨ q)

It is false that the battery is charged or the tablet turns on.

That is the same as: the battery is not charged and the tablet does not turn on.

Answer: It is false that the battery is charged or the tablet turns on.

4
Which expression matches “Leah has a pencil or an eraser, and she has paper”?
A. p ∨ (q ∧ r)
B. (p ∨ q) ∧ r
C. p ∧ q ∧ r
D. p ∨ q ∨ r
Show Answer

“Or” joins pencil and eraser inside parentheses.

AND paper is outside.

(p ∨ q) ∧ r

Answer: B

5
p: The charger is plugged in. q: The phone is on. Write ∼(p ∧ q) in words.
Show Answer

∼(p ∧ q)

It is false that the charger is plugged in and the phone is on.

Answer: It is false that the charger is plugged in and the phone is on.

6
p: The bus is late. q: We walk. r: We text. Write (∼p ∨ q) ∧ r in words.
Show Answer

(∼p ∨ q) ∧ r

The bus is not late or we walk, and we text.

Answer: The bus is not late or we walk, and we text.

7
p: The window is open. q: The fan is on. Write ∼p ∨ ∼q in words.
Show Answer

∼p ∨ ∼q

The window is not open, or the fan is not on.

Answer: The window is not open, or the fan is not on.

8
p: The lock is set. q: The alarm is on. r: We left. Write p ∧ (q ∨ r) in words.
Show Answer

p ∧ (q ∨ r)

The lock is set, and the alarm is on or we left.

Answer: The lock is set, and the alarm is on or we left.

9
p: Sam packed fruit. q: Sam packed nuts. r: Sam packed water. Write ∼(p ∨ q) ∧ r in words.
Show Answer

∼(p ∨ q) ∧ r

It is false that Sam packed fruit or nuts, and Sam packed water.

Answer: It is false that Sam packed fruit or nuts, and Sam packed water.

10
p: The printer has paper. q: The printer has ink. Write ∼p ∧ q in words.
Show Answer

∼p ∧ q

The printer does not have paper, and the printer has ink.

Answer: The printer does not have paper, and the printer has ink.

11
p: The museum is open. q: It is Monday. r: We buy tickets. Write (p ∧ ∼q) ∨ r in words.
Show Answer

(p ∧ ∼q) ∨ r

The museum is open and it is not Monday, or we buy tickets.

Answer: The museum is open and it is not Monday, or we buy tickets.

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