Divisibility Rules
Factors
Prime & Composite
Prime Factorization
GCF
100
Is 243 divisible by 2? Why or why not?
No because it doesn't end in 0,2,4,6,8 (it is not even).
100
What number is a factor of everything?
1
100
What is the only even prime number?
2
100
Find the prime factorization of 25. (Make a factor tree and write out your answer)
25=5x5
100
Find the GCF of 3 and 17.
GCF=1
200
Is 43,870 divisible by 5? Why or why not?
Yes because is ends in 0.
200
List all the factors of 19.
1,19
200
Is 37 prime or composite?
Prime
200
Find the prime factorization of 41. (Make a factor tree and write out your answer)
41=41
200
Find the GCF of 15 and 35.
15=3x5, 35=5x7, GCF=5
300
Is 10,405 divisible by 10? Why or why not?
No because it doesn't end with a 0.
300
List all the factors of 14.
1,2,7,14
300
Is 19 prime or composite?
Prime
300
Find the prime factorization of 8. (Make a factor tree and write out your answer)
8=2x2x2
300
Find the GCF of 24 and 66.
24=2x2x2x3, 66=2x3x11, GCF=2x3=6
400
We only use the digital sum for ___ and ___. Not for 2s and not for 5s, not for 10s.
3, 9
400
List all the factors of 27.
1,3,9,27
400
Is 0 prime or composite?
neither
400
Find the prime factorization of 32. (Make a factor tree and write out your answer)
32=2x2x2x2x2
400
Find the GCF of 27 and 33.
27=3x3x3. 33=3x11, GCF=3
500
Is 7,422 divisible by 3? Why or why not?
Yes because 7+4+2+2=15 which is divisible by 3.
500
List all the factors of 40.
1,2,4,5,8,10,20,40
500
Is 87 prime or composite?
Composite
500
Find the prime factorization of 34. (Make a factor tree and write out your answer)
34=2x17
500
What does the G, C and F stand for in GCF?
Greatest Common Factor
M
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