Pre-Algebra Chapter 4 Review

Which best describes the number 89?

• prime

• composite

Answer explanation

DEFINITIONS:

Numbers are prime if they do not have any other factors besides 1 and itself

Numbers with factors besides 1 and itself are composite

-89 is only divisible by 1 and 89

-89 is prime

Tags

CCSS.4.OA.B.4

Which best describes the number 105?

• prime

• composite

Answer explanation

DEFINITIONS:

Numbers are prime if they do not have any other factors besides 1 and itself

Numbers with factors besides 1 and itself are composite

-105 is divisible by 1, 3, 5, 7

-105 is composite

Tags

CCSS.4.OA.B.4

Write the prime factorization of 252.

Mathematical Equivalence

ON

Answer explanation

Tags

CCSS.8.EE.A.1

What is the GCF of 18 and 70?

Answer explanation

What is the GCF of 126 and 90?

Answer explanation

Mathematical Equivalence

ON

Answer explanation

Mathematical Equivalence

ON

Answer explanation

Which best describes the following pair of numbers?

165 and 54

• relatively prime

• not relatively prime

Answer explanation

DEFINITIONS

Two values are relatively prime if they do not share any common factors besides 1

-165 and 54 are both divisible by 3, therefore they share at least one other common factor besides 1

-they are NOT relatively prime

• relatively prime

• not relatively prime

Find the LCM of 15 and 33.

Answer explanation