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Prerequisite to chapter 5. Divisibility Rules: To determine the rules of divisibility. Divisible. When one number can be divided by another and the result is an exact whole number. Example: 15 is divisible by 3, because 15 ÷ 3 = 5 exactly
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Prerequisiteto chapter 5 Divisibility Rules: To determine the rules of divisibility
Divisible When one number can be divided by another and the result is an exact whole number. Example: 15 is divisible by 3, because 15 ÷ 3 = 5 exactly But 9 is not divisible by 2 because 9 ÷ 2 is 4 with 1 left over.
Divisibility Rules • A method that can be used to determine whether a number is evenly divisible by other numbers. • They are a shortcut for testing a number's factors without resorting to division calculations.
Here are the Divisibility Rules! A number is divisible by… • 2 if the ones digit is even ex. 542 1264 234,567 236,794 • 3 if the sum of the digits is divisible by 3 ex. 447 135 240 4,408 • 4 if the number formed by the last two digits is divisible by 4 ex. 240 4,408 234 624
Here are the Divisibility Rules! A number is divisible by… • 5 if the ones digit ends in a 5 or 0 ex. 45 3,490 546 235 • 6 if the number is divisible by BOTH 2 and 3 ex. 7,026 3498 8,903 8,440
Here are the Divisibility Rules! • 9 if the sum of the digits is divisible by 9 ex. 1,287 8,901 2,984 50,319 10 if the ones digit ends in 0 ex. 1,450 570 3,456 5,490
Lets try a few! Is the first number divisible by the second number? • 447;3 Yes • 419;2 No • 7,026;6 Yes
A few more… • 1,287;9 yes 5. 1,260;10 yes • 4,480;4 yes • 8,930 no
Determine whether each number is divisible by 2,3,4,5,6,9, or 10. 712 2,4 462 2,3,6 50,319 3,9 8,340 2,3,4,5,6,10
You try these! 8,901 3,9 1,005 3,5 920 2,4,5,10 3,498 2,3,6
On your own Page 554 Numbers 1-23 odd
Chapter 5 FRACTIONS, DECIMALS AND PERCENTS
Lesson 1 Prime Factorization Objective: find the prime factorization of a composite number
Refresh your memories! Factor: Number to a multiplication problem 3 x 6 = 18 2 x 4 x 3 = 24 Product: the answer to a multiplication problem
Whole number greater than 1 that has exactly two factors: 1 and itself. 2 (1 x 2) 3 (1 x 3) 5 (1 x 5) Prime Number
Composite Number Whole number greater than 1 that has more than 2 factors. 4 (1x4 2 x 2) 6 (1x6 2x3) 12 (1x12 2x6 3x4)
Determine whether each number is prime or composite. 17 Prime (1 x 17) 12 Composite (1x12 2 x 6 3 x 4) 11 Prime (1 x 11)
Determine whether each number is prime or composite. 15 Composite (1 x 15 3 x 15) 24 Composite (1x24 2x12 3x8 4x6)
Every composite number can be written as a product of prime numbers in exactly one way.
Prime Factorization Expressing a composite number as a product of prime numbers.
Factor tree A diagram showing the prime factorization of a number. The factors branch out from the previous factors until all of the factors are prime numbers.
Here is a model! 96 6 16 • 3 2 8 2 4 2 2 2 x 3 96 12 8 3 4 4 2 2 2 2 2 2 x 3 5 5
Lets try more 18 28
You try these! 16 30
Here are two more! 22 43
Do Now Find the prime factorization of… 46 And 108
Factor each expression 2 10ac 16x
You try these expressions! 2 2 2 52gh 48a b
You try some on your own! Page 199 numbers 13-35 odd Homework • Page 199 numbers 12-34 even • Page 554 numbers 2-24 even • You have a quiz on these 2 lessons Wednesday!