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# Divisibility Rules - PowerPoint PPT Presentation

Divisibility Rules. Introduction to Bits and Pieces III. The divisibility rules make math easier! Did you ever wonder how people could tell if something was divisible by a number just by looking at it? These rules are how they do it!

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## PowerPoint Slideshow about ' Divisibility Rules' - claude

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### Divisibility Rules

Introduction to Bits and Pieces III

• The divisibility rules make math easier!

• Did you ever wonder how people could tell if something was divisible by a number just by looking at it?

• These rules are how they do it!

• Memorize a few simple rules and simplifying fractions and prime factorization will be so much easier.

Divisibility Rules

• A number is divisible by 2 if

• It is an even number, or

• If the last digit of the number is even (0,2,4,6,8)

• An example is 54,802.

• What is another example? Come up with your own.

Divisibility Rule for 2

• A number is divisible by 3 ifthe sum (answer to an addition problem) of the digits is divisible by 3.

• An example is 642.

• 6 + 4 + 2 = 12 and 12 is divisible by 3, therefore 642 is divisible by 3.

• What is another example? Come up with your own.

Divisibility Rule for 3

Divisibility Rule for 4

Divisibility Rule for 5

• A number is divisible by 6 if the number is divisible by both 2 and 3 (because 2 x 3 = 6).

• An example is 72. 72 is even so it is divisible by 2. Also, the sum of the digits of 72 (7 + 2 = 9) is divisible by 3. Therefore, 72 is divisible by 6.

• What is another example? Come up with your own.

Divisibility Rule for 6

• A number is divisible by 8 if both 2 and 3 (because 2 x 3 = 6).the last three digits are divisible by 8 (not as easy a rule).

• An example is 35,120. 120 is divisible by 8, therefore, 35,120 is divisible by 8.

• What is another example? Come up with your own.

Divisibility Rule for 8

• A number is divisible by 9 if the sum of the digits is divisible by 9 (almost the same rule as 3).

• An example is 45. 4+5 = 9, therefore 45 is divisible by 9.

• Another example is 864. 8+6+4=18, therefore 864 is divisible by 9.

• What is another example? Come up with your own.

Divisibility Rule for 9

Divisibility Rule for 10

Divisibility Rule for 12

Divisibility Rule for 15