Tuesday, September 21AgendaFill in plannerPractice 4-1Enrichment 4-1 (E.C.)Bell WorkGo over Ch. 1 TestNotetaking WS (Divisibility and Factors)Group WorkBell Work

Objective: Students will be able to identify factors and use divisibility rules

Divisible BY

What does it mean?

Divisible by means:If you divide one number by another, the result is a whole number WITHOUT a remainder.

Examples:12 6 = 2 No remainder15 5 = 3 No remainder

Divisibility Rule 2A number is divisible by 2 if it ends in 0, 2, 4, 6, or 8.

Examples:783470

Now You Try:Which number IS NOT divisible by 2?5721464249Need More Practice: Numbers Divisible by 2

WONDERFUL

It ends in a 0, 2, 4, 6, or 8.

Divisibility Rule 5A number is divisible by 5 if it ends in 0 or 5.

Examples:615ends in a 51480ends on a 0

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

9820 779 560Need More Practice: Numbers Divisible by 5

The number ends in a zero or a five.

Wonderful

Divisibility Rule 10A number is divisible by 10 if it ends in 0

Examples:13201320 10 = 132

100100 10=10

Now You Try:Which number IS NOT divisible by 10?5604101180

WONDERFUL

The last digit is 0.

numbers end in 0, 2, 4,6, or 8 and are divisible by

numbers end in 1, 3, 5, 7, or 9 and are not divisible by 2

Divisibility Rule 3A number is divisible by three if the sum of the digits is divisible by 3.Examples:75 7 + 5 = 12 12 3 = 4 No Remainder 369 3 +6 + 9 = 18 18 3 = 6 No Remainder

Now You Try:Which number IS NOT divisible by 3?5721464279Need More Practice: Numbers Divisible by 3

The sum is divisible by 3.

WONDERFUL

Divisibility Rule 9A number is divisible by 9 if the sum of the digits is divisible by 9.

Examples:963 9 + 6 + 3 = 18 18 9 = 254455 + 4 + 4 + 5 =18 18 9 =2

Now You Try:Find the number that IS NOT divisible by 9.

98736305541

Need More Practice: Numbers Divisible by 9

The sum of the digits is divisible by 9.

Great Job!!!

FactorsOne integer is a factor of another integer if it divides that integer with a remainder of zero.

Ex. factors of 201, 202, 104,5The factors of 20 are 1, 2, 4, 5, 10, 20

Examples1) Divisibility by 2, 5, and 101028 by 2 ; 1028 ends in572 by 5 ; 572 doesnt end in or c) 275 by 10 ; 275 doesnt end in

Examples2) Divisibility by 3 and 91028 by 3 1+0+2+8=11; 11 is not divisible by 522 by 9 ; 5+2+2=9; 9 is divisible by

Examples3) Using FactorsFind pairs of factors of 35

1 x 355 x 7

There can be 5 rows of students or 7 rows of students.

Quick CheckYes; the last digit is 0No; the last digit is not 0No; the last digit is not 0, 2, 4, 6, or 8Yes; the last digit is 2No; the sum of the digits is not divisible by 9No; the sum of the digits is not divisible by 3Yes; the sum of the digits is divisible by 3Yes; the sum of the digits is divisible by 9

Quick Check (2)1, 2, 5, 101, 3, 7, 211, 2, 3, 4, 6, 8, 12, 241, 31

Quick Check (3)There could be 6 rows of 6 students, 4 rows of 9 students or 9 rows of 4 students.

Objective: Students will be able to identify factors and use divisibility rules

Definition Prime Number a number that has only two factors, itself and 1.77 is prime because the only numbersthat will divide into it evenly are 1 and 7.

Examples of Prime Numbers2, 3, 5, 7, 11, 13, 17, 19Special Note:One is not a prime number.

Definition Composite number a number that has more than two factors.8The factors of 8 are 1, 2, 4, 8

Examples of Composite Numbers4, 6, 8, 9, 10, 12, 14, 15Special Note:Every whole number from 2 on iseither composite or prime.

Our Lonely 1Special Note:One is not a prime nor a composite number.It is not primebecause it doesnot have exactlytwo differentfactors.It is not compositebecause it doesnot have morethan 2 factors.