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Divisibility Chapter 4 Section 1
“Divisible BY”
What does it mean?
“Divisible by” means:
If you divide one number by another, the
result is a whole number WITHOUT a
remainder.
Examples:
12 ÷ 6 = 2 No remainder
15 ÷ 5 = 3 No remainder
Divisibility
Why learn divisibility?
•For the same reasons you memorize
BASIC math FACTS
•It makes MATH a little easier. If you
don’t learn divisibility, you may take
LONGER and have more TROUBLE.
Divisibility Rule 2
If the last digit of the number is
even, then you know that 2 is a
factor. (0, 2, 4, 6, 8)
Examples:
78
Review Even numbers: ghosteven
3470
Now You Try:
Which number IS NOT divisible by 2?
572
1464
Need More Practice: Numbers Divisible by 2
249
WONDERFUL
It ends in a 0,
2, 4, 6, or 8.
Divisibility Rule 3
If the sum of the digits is divisible by 3,
then you know 3 is a factor.
Examples:
75
369
7 + 5 = 12 12 ÷ 3 = 4 No Remainder
3 +6 + 9 = 18
18 ÷ 3 = 6 No Remainder
Now You Try:
Which number IS NOT divisible by 3?
572
1464
Need More Practice: Numbers Divisible by 3
279
The sum is
divisible by 3.
WONDERFUL
Divisibility Rule 4
If the last two digits of the number are
divisible by 4, then 4 is a factor.
Examples:
1320 20 ÷ 4 = 5
672
72 ÷ 4 = 18
Now You Try:
Which number IS NOT divisible by 4?
564
4101
Need More Practice: Numbers Divisible by 4
188
WONDERFUL
The last 2 digits are
divisible by 4.
Divisibility Rule 5

If the number ends in 0 or 5, then
you know 5 is a factor.
Examples:
615
1480
ends in a 5
ends on a 0
Now You Try:
Which number IS NOT divisible by 5?
9820
779
Need More Practice: Numbers Divisible by 5
560
The number ends in a
zero or a five.
Wonderful
Divisibility Rule 6

If the number PASSES the tests for 2 and 3
then 6 is a factor.
Examples:
408 ends in an even number (2 rule)
sum of the digits is divisible by 3
Review prime and composite numbers: Prime and Composite Numbers
Now You Try:
Which number IS NOT divisible by 6?
8700
523
Need more practice? Numbers Divisible by 6
7602
Way To Go!!
This number is divisible
by 2 and 3.
Divisibility Rule 8
If the last 3 digits of the number are divisible by
8, then 8 is a factor.
Examples:
70,008 is divisible by 8 because 008 is a
divisible by 8
Now You Try:
Which number IS NOT divisible by 8?
1,470
7,120
1,590
Way To Go!!
NO
Divisibility Rule 9
If the sum of the digits is divisible by 9,
then 9 is a factor.
Examples:
963 9 + 6 + 3 = 18 18 ÷ 9 = 2
5445 5 + 4 + 4 + 5 =18 18 ÷ 9 =2
Now You Try:
Find the number that IS NOT divisible by
9.
9873
636
5541
Need More Practice: Numbers Divisible by 9 and 10
The sum of the digits is
divisible by 9.
Great Job!!!
Divisibility Rule 10
If the number ends in 0, then you know
that 10 is a factor.
Example:
7630 ends in a zero
410
ends in a zero
Now You Try:
Find the number that IS NOT divisible by
ten.
56,920
7537
870
The number ends in a ZERO.
Way To Go!!
Congratulations!
Complete two of the three assignments.
You may complete them on your
computers but print out your answer
sheet.
Assignment 1.doc
chart.doc
assignment3.doc
Now that you have
completed your two
assignments, feel free to
go to the following sites.
THEY ARE SOOOOO MUCH
FUN!!!!!!
Fractions
vectorkids -divisibility rules
Gamequarium Division Games