Multiples, Factors, and Prime Numbers
Finding patterns in numbers
Multiples, Factors, and Prime Numbers
Finding patterns in numbers
Math - Grade 4-5
- 1
List the first 5 multiples of 4.
Start at 4 and keep adding 4.
The first 5 multiples of 4 are 4, 8, 12, 16, and 20. - 2
List all the factors of 12.
The factors of 12 are 1, 2, 3, 4, 6, and 12 because each of these numbers divides 12 evenly. - 3
Tell whether 17 is prime or composite. Explain how you know.
Check whether any numbers besides 1 and 17 divide it evenly.
The number 17 is prime because it has exactly 2 factors, 1 and 17. - 4
Write the first 6 multiples of 7.
The first 6 multiples of 7 are 7, 14, 21, 28, 35, and 42. - 5
Find all the factor pairs of 18.
Look for two numbers that multiply to make 18.
The factor pairs of 18 are 1 and 18, 2 and 9, and 3 and 6. - 6
Circle all the prime numbers: 9, 11, 13, 15, 19.
The prime numbers are 11, 13, and 19 because each has exactly 2 factors. - 7
Find the greatest common factor of 8 and 12.
List the factors of each number and find the greatest one they share.
The greatest common factor of 8 and 12 is 4 because 4 is the largest number that divides both 8 and 12 evenly. - 8
Find the least common multiple of 3 and 5.
The least common multiple of 3 and 5 is 15 because 15 is the smallest number that is a multiple of both 3 and 5. - 9
Is 21 a multiple of 3, a factor of 42, or both? Explain.
Check multiplication and division facts for 21.
The number 21 is both because 21 equals 3 times 7, so it is a multiple of 3, and 42 divided by 21 equals 2, so it is a factor of 42. - 10
List all the factors of 20.
The factors of 20 are 1, 2, 4, 5, 10, and 20. - 11
Write the first 4 common multiples of 2 and 3.
Find numbers that appear in both the multiples of 2 and the multiples of 3.
The first 4 common multiples of 2 and 3 are 6, 12, 18, and 24. - 12
Tell whether 1 is prime, composite, or neither. Explain your thinking.
The number 1 is neither prime nor composite because it has only 1 factor. - 13
Find the missing number: 5, 10, 15, __, 25. Tell what pattern you used.
Look at how much the numbers increase each time.
The missing number is 20. The pattern is counting by 5s, so each number is a multiple of 5. - 14
Find the greatest common factor of 15 and 25.
The greatest common factor of 15 and 25 is 5 because 5 is the largest factor they both share. - 15
A number has exactly 2 factors, 1 and itself. What kind of number is it? Give one example.
Think about the definition of a prime number.
This kind of number is called a prime number. One example is 7 because its only factors are 1 and 7.