Download Divisibility and Prime Factorization Review Name ANSWER KEY

Divisibility and Prime Factorization Review
Name ANSWER KEY
Using Divisibility Rules:
YES
1.
Is 5,781 divisible by 3? Why or why not? Sum of the digits (21) is divisible by 3
NO
2.
Can 6 divide into 5,781 evenly? Why or why not? It is divisible by 3 but is NOT divisible by 2
YES
3.
Is 2,340 divisible by 4?
NO
4.
Is 9,803 divisible by 3?
5.
How can you decide if a number is divisible by 9?
6.
Ms. Randall is planning to seat 150 guests at her wedding reception. She wants to arrange tables
so that every table is the same size and every table is full. The available tables seat 4, 5, 6, and 9.
Which size tables could Ms. Randall have? Circle all options possible and explain how many tables
would be needed.
a. Seats 4 people
b. Seats 5 people
c. Seats 6 people
d. Seats 9 people
__x___ tables
_30_ tables
25 tables
___x__ tables
If the sum of the number is divisible by 9
Prime and Composite Numbers:
B
B
B
_ 7.
_ 8.
_
Is 81 prime or composite?
a.
PRIME
b. COMPOSITE
Which of the following is a prime number?
a.
99
b. 13
9. Which is NOT a factor of 260?
a.
4
b. 3
c. 6
c. 13
d. 21
d. 10
Create a T-Chart for the following numbers. Then tell how many factors.
10.
63
6
factors
11.
57
4
factors
16
factors
12. 120
13.
Which of the following is a factor pair of 24? B
a.
2, 21
b. 3, 8
c. 4, 12
Write each product using an exponent.
14.
5 x 5 x 5
15.
10 x 10 x 10
16.
8 x8 x8
17.
12 x 12
18. 3 x 3 x 3
= 53
4
x 10 = 10
= 83
= 122
= 33
d. 3, 24
Write each power as a product of the same factor.
19.
36 = 3 x 3 x 3 x 3 x 3 x 3
22.
five squared ( 52 ) = 5 x 5
20.
43 = 4 x 4 x 4
23.
112
21.
105 = 10 x 10 x 10 x 10 x 10
24.
nine squared (92) = 9 x 9
= 11 x 11
CAKE METHOD: Write the prime factorization of each number using exponents.
25.
21 =
3x7
28.
15 =
3x5
26.
88 =
2 x 2 x 2 x 11
29.
99 =
3 x 3 x 11
27.
100 =
2 x 2 x 5 x 5
30.
78 =
2 x 3 x 13
Multiple Response:
Identify one or more choices that best complete the statement or answer the question.
B, D
31.
B, D, E
B, C
32.
33.
A, D, E
34.
Which of the following are divisible by 4?
a. 135
b. 732
c 442
d. 836
By which of the following is 60,070 NOT divisible?
a. 2
b. 3
c. 5
d. 6
e. 9
f. 10
Which of the following are PRIME numbers?
a. 111
b. 13
c. 37
e. 9
f. 3
e. 732
f. 17
d. 21
Which of the following are COMPOSITE numbers?
a. 99
b. 2
c. 0
d. 36
35. What number has only one distinct factor?
1
36. A number is divisible by 2 and 5. What other number must it be divisible by?
Parent Signature: ___________________________________________
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