Download Are these numbers divisible by 2?

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What is Divisibility?
Divisibility means that after
dividing, there will be No remainder.
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356,821
Can you tell by just looking at this
number if it is divisible by 2?
by
by
by
by
By
5?
The
divisibility
10?
3 ?rules can help YOU!
9?
6?
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Divisibility Rules
help you learn shortcuts to tell
when a number can be divided by
another number with
NO REMAINDER.
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Dividing By 1
All numbers are divisible by 1
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Now You Try
Are these numbers divisible by 1?
a) 578
b) 1201
c) 465
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Dividing by 2
All even numbers are divisible by 2
18 ÷ 2 = 9
22 ÷ 2 = 11
Notice that both of these numbers are even.
21 ÷
2 = 10 R1 NOT
EVEN
Even numbers are numbers that
end with either 2, 4, 6, 8, or 0
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Now You Try
Are these numbers divisible by 2?
a) 458
b) 1279 Not an even number
c) 759 Not an even number
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Dividing by 3
A number is divisible by 3 if the
sum of the digits is divisible by 3.
Is the number 135 divisible by 3?
Add the digits: 1 + 3 + 5 = 9
Yes, 135 is divisible by 3 because the
sum of the digits is divisible by 3.
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Now You Try
Are these numbers divisible by 3?
a) 639
b) 56
c) 738
Sum of 6+3+9 =18
Sum of 5+6 =11
NO
Sum of 7+3+8 =18
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Dividing by 4
If the last 2 digits together are divisible by 4
Example
384
21
4) 84
or take your number, divide it by 2. Then
divide that answer by 2, and if you get an
EVEN NUMBER then it is divisible by 4
Example
360
180 EVEN
2) 360
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90 EVEN
2) 180
Now You Try
Are these numbers divisible by 4?
a) 584
21
4) 84
b) 261
15 r1
4) 61
NO
Take the last 2 digits and divide by 4
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Dividing by 5
If the number ends in 5 or 0
25 ÷ 5 = 5
23 ÷ 5 = 4 R3
NO
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Now You Try
Are these numbers divisible by 5?
a) 554
b) 6890
c) 345
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Dividing by 6
If the number is divisible by 2,
AND . . .
If the number is divisible by 3
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Now You Try
Are these numbers divisible by 6?
a) 897 No
b) 258
c) 630
it is not EVEN
EVEN, Sum of 2+5+8
=15
EVEN, Sum of 6+3+0
=9
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Dividing by 7
There is no special rule to help you
know if a number is divisible by 7…
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Now You Try
Are these numbers divisible by 7?
a) 500
b) 49
c) 2100
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Dividing by 8
If the last three digits are divisible by 8
If the number is divisible by 2,
then by 2 again, and then by 2 again
2 8
222 = 8
3
So what type of number does it have to be?
A number that has been cubed.
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Now You Try
Are these numbers divisible by 8?
a) 568
284 Even
142 Even
71
2) 568
2) 284
2) 142
b) 396
198 Even
99 Odd
2) 396
2) 198
NO
Take the last 3 digits and divide by 2,
then divide by 2, then divide by 2
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Dividing by 9
Similar to dividing by 3
Add up digits
If that number is divisible by 9 then
your number is divisible by 9
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Dividing by 9
For example, take the number
924,561
Add up the digits of the number
9 + 2 + 4 + 5 + 6 + 1 =
27
If that number is divisible by 9, then the
original number is Is 27 divisible by
9?
If your sum is still a big number, continue to
add the digits
2+7=9
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Now You Try
Are these numbers divisible by 9?
a) 578
Sum of 5+7+8 =20 NO
b) 399
Sum of 3+9+9 =21 NO
c) 144 Sum of 1+4+4 =9
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Dividing by 10
If the number ends with a 0
30 ÷ 10 = 3
340 ÷ 10 = 34
67 ÷ 10 = 6 R7
784 ÷ 10 =78 R4
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Now You Try
Are these numbers divisible by 10?
a) 5782
b) 390
c) 45
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Dividing by 11
There is no special rule to
help you know if a number is
divisible by 11…
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Now You Try
Are these numbers divisible by 11?
a) 99
b) 88
c) 121
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REVIEW
Thumbs up if you remember the rule.
Divisible by 1
Divisible by 2
Divisible by 3
Divisible by 4
Divisible by 5
Divisible by 6
Divisible by 7
Divisible by 8
Divisible by 9
Divisible by 10
Divisible by 11
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After All… DIVISIBILITY Rules
Take Out Your Study Guide!!!
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#1
RULES FOR DIVISIBILITY
IF
A Number Is
Divisible By:
2
3
4
5
6
8
9
10
The last digit is even (0, 2, 4, 6, 8)
The sum of the digits is divisible by 3
The last 2 digits are divisible by 4 (÷2÷2)
The last digit is 0 or 5
It is divisible by 2 and 3
The last 3 digits are divisible by 8 (÷2÷2÷2)
The sum of the digits is divisible by 9
The last digit is 0
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#2
IS THE NUMBER DIVISIBLE EXACTLY BY?
WRITE yes (y) or no (n) REMEMBER: Show the
sums for 3, and show the division for 4 and 8.
Number
2
3
1)
360
y
3+6 = 9
y
4
30
2) 60
15
2) 30
y
5
y
6
y
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8
180
2)360
90
2)180
45
2) 90
y
9
y
10
y