1. Tuesday, September 21 Agenda Bell Work Fill in planner Bell Work
Practice 4-1
Enrichment 4-1 (E.C.)
Bell Work
Go over Ch. 1 Test
Notetaking WS (Divisibility and Factors)
Group Work

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

3. “Divisible BY” What does it mean?

4. “Divisible by” means:
If you divide one number by another, the result is a whole number WITHOUT a remainder.
Examples:
12 ÷ 6 = 2 No remainder
15 ÷ 5 = 3 No remainder

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

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

7. WONDERFUL

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

9. Divisibility Rule 5 A number is divisible by 5 if it ends in 0 or 5.
Examples:
615 ends in a 5
1480 ends on a 0

10. Now You Try: 9820 779 560 Which number IS NOT divisible by 5?
Need More Practice: Numbers Divisible by 5

11. The number ends in a zero or a five.

12. Divisibility Rule 10 A number is divisible by 10 if it ends in 0
Examples:
÷ 10 = 132
÷ 10 =10

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

14. WONDERFUL

15. The last digit is 0.

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

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

18. Divisibility Rule 3
A number is divisible by three if the sum of the digits is divisible by 3.
Examples:
= ÷ 3 = 4 No Remainder
= ÷ 3 = 6 No Remainder

19. Now You Try: 572 1464 279 Which number IS NOT divisible by 3?
Need More Practice: Numbers Divisible by 3

20. The sum is divisible by 3.

21. WONDERFUL

22. Divisibility Rule 9
A number is divisible by 9 if the sum of the digits is divisible by 9.
Examples:
= ÷ 9 = 2
= ÷ 9 =2

23. Now You Try: 9873 630 5541 Find the number that IS NOT divisible by 9.
Need More Practice: Numbers Divisible by 9

24. The sum of the digits is divisible by 9.

25. Great Job!!!

26. Factors
One integer is a factor of another integer if it divides that integer with a remainder of zero.
Ex. factors of 20
1, 20
2, 10
4,5
The factors of 20 are 1, 2, 4, 5, 10, 20

27. Examples 1) Divisibility by 2, 5, and 10
1028 by ; 1028 ends in
572 by ; 572 doesn’t
end in or
c) 275 by ; 275 doesn’t
end in 8
yes no 5 no

28. Examples 2) Divisibility by 3 and 9
1028 by =11; 11 is not divisible by
522 by ; 5+2+2=9; 9 is divisible by no 3
yes 9

29. Examples 3) Using Factors
Find pairs of factors of 35
1 x 35
5 x 7
There can be 5 rows of students or 7 rows of students. 7 5

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

31. Quick Check (2)
1, 2, 5, 10
1, 3, 7, 21
1, 2, 3, 4, 6, 8, 12, 24
1, 31

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

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

34. 7 Definition 7 is prime because the only numbers
Prime Number – a number that has only two factors, itself and 1. 7
7 is prime because the only numbers
that will divide into it evenly are 1 and 7.

35. Examples of Prime Numbers
2, 3, 5, 7, 11, 13, 17, 19
Special Note:
One is not a prime number.

36. 8 Definition The factors of 8 are 1, 2, 4, 8
Composite number – a number that has more than two factors. 8
The factors of 8 are 1, 2, 4, 8

37. Examples of Composite Numbers
4, 6, 8, 9, 10, 12, 14, 15
Special Note:
Every whole number from 2 on is
either composite or prime.

38. Our Lonely 1 One is not a prime nor a composite number.
It is not prime
because it does
not have exactly
two different
factors.
It is not
composite
because it does
not have more
than 2 factors.
Special Note:
One is not a prime nor
a composite number.