Prime factorization, factors, & divisibility rules

What is the prime factorization of 16?

• 3³

• 2² x 4

• 2⁴

• 8 + 8

What is the prime factorization of 72?

• 2 x 4 x 9

• 2³ x 3²

• 3 x 4²

• 2² x 3 x 6

A composite number

• has more than 2 factors

• has one factor

• has at least 10 factors

• is always a really big number

A prime number

• has one factor
• has more than 2 factors
• has 100 factors
• has exactly 2 factors: 1 and the number

The divisibility rule for 9 is...

• Divide the whole thing by nine
• Add the digits together.  If the sum is divisible by 9, the original number is divisible by 9
• Multiply the digits together by 9
• Add the digits together and then add 9.

What numbers can divide into 111 ?

• 6

• 3

• 4

• 11

Which of these numbers is divisible by 3 AND 5?

• 85
• 115
• 73
• 105

How do you know if a number is divisible by 3?

• If the sum of the digits is a multiple of 3
• If it ends in 3, 6, or 9
• If it is an even number
• If it ends in 0 or 5

Is 2,385 divisible by both 5 and 9?

• Yes

• No

What are the prime numbers between 20 and 30?

• 23, 29

• 21, 23, 29

• 21, 23, 27, 29

• 21, 23, 25, 29