# Divisibility Rules and Number Theory

## Presentation on theme: "Divisibility Rules and Number Theory"— Presentation transcript:

Divisibility Rules and Number Theory
5-Minute Frenzy Math Notebook Divisibility Rules and Number Theory Schedule:

Multiplication Pg. 3 Division Pg. 4 Divisibility Rules Pg. 5

12 ÷ 6 = 2 15 ÷ 5 = 3 “Divisible by” means:
It goes into the other number without a remainder! Examples: 12 ÷ 6 = ÷ 5 = 3

Number: 2 A number is divisible by 2 if the last digit is even. (0, 2, 4, 6, 8) Examples:

Now You Try: 572 1464 249 Need More Practice: Numbers Divisible by 2
Which number IS NOT divisible by 2? Need More Practice: Numbers Divisible by 2

Number: 3 *Hint add the digits and see if you can divide that number by 3 Examples: 7 + 5 = ÷ 3 = 4

Circle all of the numbers
That are divisible by 3! 20 42 48 39 35 24 6 30

Number: 5 A number is divisible by 5 if the last digit is a 0 or 5. Examples: 615 ends in a ends on a 0

Now You Try: Which number IS NOT divisible by 5?

Number:10 A number is divisible by 10 is if it ends in a ZERO. Example: 7630 ends in a zero 410 ends in a zero

Find the number that IS NOT divisible by ten.
Now You Try: Find the number that IS NOT divisible by ten. 56,

Number: 4 A number is divisible by 4 if the last two digits are divisible by 4. Examples: ÷ 4 = ÷ 4 = 18

Which number IS NOT divisible by 4?
Now You Try: Which number IS NOT divisible by 4? Need More Practice: Numbers Divisible by 4

Number: 6 A number is divisible by 6 when it is divisible by 2 AND 3. Examples: 408 ends in an even number (2 rule) sum of the digits is divisible by 3

Which number IS NOT divisible by 6?
Now You Try: Which number IS NOT divisible by 6?

Number: 9 A number is divisible by 9 if the sum of the digits is divisible by 9. Example: 963 = 18 18 ÷ 9 = 2

Number Theory What does that mean?

What is an even number? Can be divided by 2
Unit digit is 0, 2, 4, 6, or 8 Is a multiple of 2 782,444 4 608

What is an odd number? Cannot be divided by 2
Unit digit is 1, 3, 5, 7, or 9 Is not a multiple of 2 782,333 5 607

EVEN + EVEN = ? 12 + 4

ODD + ODD = ? 11+9

EVEN + ODD = ? 8+7

Number Theory…