Study Guide for Chapter 6 Math Test
Test Date: Thursday, November 22, 2012
Reminder: You will not be permitted to use a calculator for this test.
Practice these questions without the use of a calculator.
Use this checklist to make sure you are prepared for Thursday’s test.
Topic 6.1
□ I can recognize when a number is divisible by two, five and ten.
A number is divisible by two when the last digit is ___________. Circle the numbers that are
divisible by two:
862 935 17
156 409 974 213 88
A number is divisible by five when the last digit is _____ or _____. List three numbers that are
divisible by 5: ________, ________, and ________.
A number is divisible by ten if and only if the last digit is _____. For example, ______ is a
number that is divisible by ten, but _____ is not divisible by ten.
□ I can recognize when a number is divisible by four and eight.
When I want to check if a number is divisible by four, I must check if it can be divided by two at
least _______ times. An example of how I check looks like this:
If I want to know if 852 is divisible by 4, first I ask, “Can I divide 852 by 2?”
Yes, 852 is divisible by 2 since it is even. 852 ÷2 = 426.
Next, I ask, “Can 426 be divided by 2?
Yes, 426 is divisible by 2 since it is even. 426 ÷2 = 213.
I know that 852 is divisible by 4 since I was able to divide it by 2 at least ______ times.
Try these examples: 1) Is 368 divisible by 4?
2) Is 450 divisible by 4?
When I want to check if a number is divisible by eight, I must check if it can be divided by two at
least ________ times. An example of how I check looks like this:
If I want to know if 128 is divisible by 8, first I ask, “Can I divide 128 by 2?”
Yes, 128 is divisible by 2 since it is even. 128 ÷2 = 64.
Next, I ask, “Can 64 be divided by 2?”
Yes, 64 can be divided by 2 since is it even. 64 ÷2 = 32.
One more time I ask, “Can 32 be divided by 2?”
Yes, 32 is divisible by 2 since it is even. 32 ÷ 2 = 16
I can conclude that 128 is divisible by 8 since I was able to divide it by 2 at least ______ times.
Try these examples: 1) Is 208 divisible by 8?
2) Is 352 divisible by 8?
□ I can recognize when a number is divisible by three and nine.
The key to finding out if a number is divisible by three or nine is using the digital sum.
digital sum the sum of the digits
When I want to know if a number is divisible by 3, I find the sum of the digits and make sure it is
divisible by _____.
Example: 891 is divisible by 3 since 8 + 9 + 1 = 18 and 18 is divisible by 3.
452 is NOT divisible by 3 since 4 + 5 + 2 = 11 and 11 is not divisible by 3.
Try these examples for divisibility by 3:
a) Is 527 divisible by 3?
b) Is 612 divisible by 3?
When I want to know if a number is divisible by 9, I find the sum of the digits and make sure it is
divisible by _____.
Example: 891 is divisible by 9 since 8 + 9 + 1 = 18 and 18 is divisible by 9.
546 is divisible NOT divisible by 9 since 5 + 4 + 6 = 15 and 15 is not divisible by 9.
Try these examples for divisibility by 9:
a) Is 450 divisible by 9?
b) Is 763 divisible by 9?
□ I can recognize when a number is divisible by six.
In order for a number to be divisible by six, it must be divisible by BOTH _______ and ________.
Circle the numbers that are divisible by 6:
870
412
53
171
102
48
81
□ I can explain why a number is not divisible by 0.
Using a pattern or a diagram, explain why a number cannot be divided by zero.
□ I can use divisibility rules to find factors.
Factors
Remember the definition of a factor:
 When a number is divisible by another number, we call the second
number a factor of the first.
**When we find factors, we follow three steps:
1) Start with 1, since 1 is a factor of every number.
2) Put the number at the other end, since every number is a factor of itself.
3) Find the pairs of factors that are in between 1 and that number.
The factors of 12 include: 1, 2, 3, 4, 6, and 12
For practice, find the factors of:
36:___________________________________________________________________________
42:___________________________________________________________________________
Common factors (factors found in both lists) are: ______________________________________
Organize the factors into a Venn diagram:
factors of 36
factors of 42
The greatest common factor of 36 and 42 is: _________________.
□ I can use factors to place fractions in lowest terms.
Practice putting these fractions in lowest terms.
20
9
=
24
15
12
7
=
18
21
10
12
=
25
20
=
=
=
Topic 6.2
□ I can use diagrams, solve word problems and numerically add fractions with like
denominators.
Using the diagram, write an addition statement, then add.
Try these addition problems. Show all your work and write the answer in lowest terms.
4
+
8
7
+
12
1
=
8
2
=
12
4
6
+
10
10
8
2
+
15
15
=
=
Topic 6.3
□ I can use diagrams, solve word problems and numerically add fractions with like
denominators.
Using the diagram, write a subtraction statement, then find the difference.
Try these subtraction problems. Show all your work and write your answer in lowest terms.
5
−
6
8
4
=
6
4
− 12 =
12
7
−
10
12
−
15
2
10
9
15
=
=