Unit 1 - Number Theory Jeopardy!

Divisibility Tests

100

Is 23,456 divisible by 2?

Yes

200

Which of these is 147 divisible by? 1 2 3 4 5 6

1 3

300

Is 55,552 divisible by 5

No

400

Is 360,021,004 divisible by 3?

No

500

Is 345 divisible by 2, 3 and/or 5

Divisible by 3 and 5 only

Factors

100

What are the factors of 7?

1, 7

200

1, 2, 3, 5, 6, 10, 30 Are these ALL of the factors of 30?

No, we are missing 15

300

These are the factors of which number? (They are not in order!) 12, 3, 4, 8, 6, 1, 24, 2

24

400

List the factors of 32

1, 2, 4, 8, 16, 32

500

List the factors of 40. Which of these are prime numbers?

1, 2, 4, 5, 8, 10, 20, 40 Only 2 and 5 are prime

Multiples & Least Common Multiples

100

8, 16, 24, 32, 40, 48... These numbers are the multiples of...

8

200

What is the Least Common Multiple of 6 and 9?

18

300

What is the Least Common Multiple of 24 and 30?

120

400

What number is the least common multiple of 16 and 30? Use prime factorization!

240

500

What is the least common multiple of 16 and 20?

80

Types of Numbers (Prime, Composite, squared)

100

What is the first prime number?

2

200

How do I find square numbers?

Multiply any number by itself

300

Is 51 a prime or composite number? Why?

Composite - It is divisible by 3, It has more than 2 factors.

400

List the first 7 primes!

2, 3, 5, 7, 11, 13, 17

500

Is 31 prime or composite? Why

Prime - It has exactly two factors: 1 and itself

Greatest Common Factors

100

What is the greatest common factors of 9 and 27?

9

200

What is the GCF of 12 and 45?

3

300

What is the GCF of 15 and 25?

75

400

What is the GCF of 24 and 40?

8

500

What is the GCF of 72 and 144?

72

GCF/LCM Word Problems

100

A radio station is having a promotion in which every 12th caller receives a free concert ticket, and every 15th caller receives a limo ride. Which caller will be the first one to win both?

Is this LCM or GCF?

LCM

200

A family is preparing backpacks filled with school supplies to donate to children in need. They have 32 pencils and 48 notebooks. If they want to make all the backpacks the same, with no school supplies left over, what is the greatest number of backpacks they can fill?

Is this GCF or LCM?

GCF

300

Camryn practices trumpet every 11th day and flute every 3rd day. She practiced both today.

How many days until she practices both on the same day again?

33 days

400

There are 72 boys and 90 girls on the math team. Mr. Johnson wants to arrange them into equal rows, with each row made up of only boys or only girls.

What is the greatest number of students that can be in each row? 

18 students

500

Evelyn and Ophelia love gardening. Evelyn waters her plants every 3 days. Her neighbor Ophelia waters her plants every 5 days. If they both water their plants on July 1, what is the next date they will water their plants together?

July 16th

- 15 days after July 1st