Prime and Composite Numbers
A number that has exactly two factors: 1 and itself.
What does it mean to order numbers from least to greatest?
To arrange numbers starting with the smallest and ending with the largest.
What is the rule for checking if a number is divisible by 2?
The last digit must be even (0, 2, 4, 6, or 8).
What is a factor?
A number that divides evenly into another number.
What is a multiple?
A number you get by multiplying a number by whole numbers (e.g., 3, 6, 9 are multiples of 3).
Is the number 29 prime or composite?
Prime
Which number is the greatest: 4,382; 3,928; 4,283; 4,832?
4,832
Is 135 divisible by 5?
yes
List all the factors of 12.
1, 2, 3, 4, 6, 12
What are the first five multiples of 4?
4, 8, 12, 16, 20
Is the number 1 a prime number?
No, it only has one factor
Order these decimals from least to greatest: 3.2, 3.02, 3.25
3.02, 3.2, 3.25
If the digits of a number add up to 18, which divisibility rule does that help you check?
Divisibility by 3, 6 and 9.
What are the prime factors of 18?
2 × 3 × 3
Name a common multiple of 3 and 5.
15 (or 30, 45, etc.)
Name three composite numbers between 10 and 20.
12, 14, 15 (or other valid combinations)
Put these numbers in order from greatest to least: 5,203; 5,230; 5,023
5,230; 5,203; 5,023
A number is divisible by both 2 and 3. What other number is it also divisible by?
6
What does a factor tree help you find?
The prime factors of a number.
What is the greatest common multiple of 6 and 8 under 100?
Trick question! Multiples go on forever — we usually look for the least common multiple instead.
I am a number less than 50. I have only two factors. I come right after a composite number. What number am I?
Any valid prime number that fits (e.g., 47 after 46)
This number is written as 6,000 + 400 + 20 + 1. What is the number,
6,421
Is 1,248 divisible by 4? Explain how you know.
Yes, because the last two digits (48) are divisible by 4.
Complete the factor tree for 48. What are the prime factors?
2 × 2 × 2 × 2 × 3
If two students are clapping every 4 and 6 seconds, when will they clap together again?
After 12 seconds (LCM of 4 and 6)