1 3
3 3 9
Divisibility
Divisible - When one number can be divided
by another and the result is an exact whole
number (an answer with no remainders).
1 2 r1
3 3 7
Divisibility Rules
Dividing by 1:
All numbers are divisible by 1.
Try dividing any number you can think of by 1.
Divisibility Rules
Dividing by 2:
If a number is even it will always divide by 2.
There is a quick way to test if a number can be divided by 2.
Simply look at the last digit. If it is even (0,2,4,6 or 8)
then the number is divisible by 2.
4070
4070
Divisibility Rules
Dividing by 3:
9 can be divided equally by
3 so 153 is divisible by 3.
153
1+5+3=9
If the sum of all the digits in
a number is a multiple of 3
then it is divisible by 3.
Divisibility Rules
Dividing by 4:
1 543 612
Look at the last two digits of
any number. If they can be
divided equally by 4 then the
whole number is divisible by
4, no matter how large the
number!
1 543 612
12 is divisible by 4.
This means that 1 543 612 is also divisible by 4.
If a number ends in 00 it is also divisible by 4.
Divisibility Rules
Dividing by 5: A simple rule for dividing by
5. If a number ends in a 0 or
a 5 then it is divisible by 5!
6240
Divisibility Rules
Dividing by 6: This rule is a little harder as
you have two steps to follow.
6924 We know it can be divided by 2
as it ends with an even number.
6+9+2+4=21 We know it can be divided by
3 because 21 is divisible by 3.
6924 can be divided by both 2
and 3 so it is also divisible by 6.
To test if a number is divisible by 6, you must
first see if you can divide it by 2 and then by 3.
Divisibility Rules
Dividing by 7:
To test if a number is divisible by 7, take the last number and double
it, then subtract it from the number made by the other digits. The
answer must be divisible by 7.
Let’s try one together with 826.
826
826
82–12=70
Double the last number.
6+6=12
Now take the number made by the other digits
and subtract 12 from this.
We can divide 70 by 7,
therefore 826 is divisible by 7.
82–12=70
Divisibility Rules
Dividing by 8:
There are no simple tests for numbers divisible by 8. However, if you
have a large number you can make it simpler by only looking at the
last three digits.
248 is divisible by 8, therefore
4567248 is divisible by 8 too.
You do not have to try dividing the
whole number, just the last 3 digits.
4567248
3 1
8 2 4 8
Divisibility Rules
Dividing by 9: Our last few rules for divisibility have
been quite tricky! But don’t worry the
rule for 9 is straight forward.
Simply add all the digits to see if the total is divisible by 9.
225
2+2+5=9
562
5+6+2=13
Divisibility Rules
Dividing by 10:
If it is a zero it will always be divisible
by 10, no matter how large the number!
153469780
To test if a number is divisible by 10 simply look at the last digit.
456
652430
Divisibility

Divisibility

  • 2.
    1 3 3 39 Divisibility Divisible - When one number can be divided by another and the result is an exact whole number (an answer with no remainders). 1 2 r1 3 3 7
  • 3.
    Divisibility Rules Dividing by1: All numbers are divisible by 1. Try dividing any number you can think of by 1.
  • 4.
    Divisibility Rules Dividing by2: If a number is even it will always divide by 2. There is a quick way to test if a number can be divided by 2. Simply look at the last digit. If it is even (0,2,4,6 or 8) then the number is divisible by 2. 4070 4070
  • 5.
    Divisibility Rules Dividing by3: 9 can be divided equally by 3 so 153 is divisible by 3. 153 1+5+3=9 If the sum of all the digits in a number is a multiple of 3 then it is divisible by 3.
  • 6.
    Divisibility Rules Dividing by4: 1 543 612 Look at the last two digits of any number. If they can be divided equally by 4 then the whole number is divisible by 4, no matter how large the number! 1 543 612 12 is divisible by 4. This means that 1 543 612 is also divisible by 4. If a number ends in 00 it is also divisible by 4.
  • 7.
    Divisibility Rules Dividing by5: A simple rule for dividing by 5. If a number ends in a 0 or a 5 then it is divisible by 5! 6240
  • 8.
    Divisibility Rules Dividing by6: This rule is a little harder as you have two steps to follow. 6924 We know it can be divided by 2 as it ends with an even number. 6+9+2+4=21 We know it can be divided by 3 because 21 is divisible by 3. 6924 can be divided by both 2 and 3 so it is also divisible by 6. To test if a number is divisible by 6, you must first see if you can divide it by 2 and then by 3.
  • 9.
    Divisibility Rules Dividing by7: To test if a number is divisible by 7, take the last number and double it, then subtract it from the number made by the other digits. The answer must be divisible by 7. Let’s try one together with 826. 826 826 82–12=70 Double the last number. 6+6=12 Now take the number made by the other digits and subtract 12 from this. We can divide 70 by 7, therefore 826 is divisible by 7. 82–12=70
  • 10.
    Divisibility Rules Dividing by8: There are no simple tests for numbers divisible by 8. However, if you have a large number you can make it simpler by only looking at the last three digits. 248 is divisible by 8, therefore 4567248 is divisible by 8 too. You do not have to try dividing the whole number, just the last 3 digits. 4567248 3 1 8 2 4 8
  • 11.
    Divisibility Rules Dividing by9: Our last few rules for divisibility have been quite tricky! But don’t worry the rule for 9 is straight forward. Simply add all the digits to see if the total is divisible by 9. 225 2+2+5=9 562 5+6+2=13
  • 12.
    Divisibility Rules Dividing by10: If it is a zero it will always be divisible by 10, no matter how large the number! 153469780 To test if a number is divisible by 10 simply look at the last digit. 456 652430