Warm Up

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Warm Up
Problem of the Day
Lesson Presentation
Lesson Quizzes
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Warm Up 1. 20 2. 48 3. 16
Write each number as a product of two whole
numbers in as many ways as possible.
1 ? 20, 2 ? 10, 4 ? 5
1 ? 48, 2 ? 24, 3 ? 16, 4 ? 12, 6 ? 8
1 ? 16, 2 ? 8, 4 ? 4
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Problem of the Day In this magic square, every
row, column, and diagonal has the same sum, 34.
Complete the square using the whole
numbers from 1 to 16.
Possible answer
14
1
4
15
9
12
8
5
13
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Learn to use divisibility rules.
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Vocabulary
divisible composite number prime number
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A number is divisible by another number if the
quotient is a whole number with no remainder.
42 6
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Quotient
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Additional Example 1A Checking Divisibility Tell
whether 462 is divisible by 2, 3, 4, and 5.
The last digit, 2, is even.
Divisible
The sum of the digits is 4 6 2 12. 12 is
divisible by 3.
Divisible
Not divisible
The last two digits form the number 62. 62 is
not divisible by 4.
Not divisible
The last digit is 2.
So 462 is divisible by 2 and 3.
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Additional Example 1B Checking Divisibility Tell
whether 540 is divisible by 6, 9, and 10.
The number is divisible by both 2 and 3.
Divisible
The sum of the digits is 5 4 0 9. 9 is
divisible by 9.
Divisible
The last digit is 0.
Divisible
So 540 is divisible by 6, 9, and 10.
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Check It Out Example 1A Tell whether 114 is
divisible by 2, 3, 4, and 5.
The last digit, 4, is even.
Divisible
The sum of the digits is 1 1 4 6. 6 is
divisible by 3.
Divisible
The last two digits form the number 14. 14 is
not divisible by 4.
Not Divisible
Not Divisible
The last digit is 4.
So 114 is divisible by 2 and 3.
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Check It Out Example 1B Tell whether 810 is
divisible by 6, 9, and 10.
The number is divisible by both 2 and 3.
Divisible
The sum of the digits is 8 1 0 9. 9 is
divisible by 9.
Divisible
The last digit is 0.
Divisible
So 810 is divisible by 6, 9, and 10.
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Any number greater than 1 is divisible by at
least two numbers1 and the number itself.
Numbers that are divisible by more than two
numbers are called composite numbers.
A prime number is divisible by only the numbers 1
and itself. For example, 11 is a prime number
because it is divisible by only 1 and 11. The
numbers 0 and 1 are neither prime nor composite.
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Click to see which numbers from 1 through 50 are
prime.
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Additional Example 2 Identifying Prime and
Composite Numbers
Tell whether each number is prime or composite.
A. 23
divisible by 1, 23
prime
B. 48
divisible by 1, 2, 3, 4, 6, 8, 12, 16, 24, 48.
composite
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Additional Example 2 Identifying Prime and
Composite Numbers
Tell whether each number is prime or composite.
C. 31
divisible by 1, 31
prime
D. 18
divisible by 1, 2, 3, 6, 9, 18
composite
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Check It Out Example 2
Tell whether each number is prime or composite.
A. 27
divisible by 1, 3, 9, 27
composite
B. 24
divisible by 1, 2, 3, 4, 6, 8, 12, 24
composite
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Check It Out Example 2
Tell whether each number is prime or composite.
C. 11
divisible by 1, 11
prime
D. 8
divisible by 1, 2, 4, 8
composite
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Lesson Quizzes
Standard Lesson Quiz
Lesson Quiz for Student Response Systems
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Lesson Quiz
Tell whether each number is divisible by 2, 3, 4,
5, 6, 9, and 10. 1. 256 2. 720 3. 615 Tell
whether each number is prime or composite. 4.
47 5. 38
2, 4
2, 3, 4, 5, 6, 9, 10
3, 5
composite
prime
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Lesson Quiz for Student Response Systems
1. Tell whether 255 is divisible by 2, 3, 4, 5,
6, 9, and 10. A. 2, 3, 4, 5, 6, 9, 10 B. 2, 3,
4, 6 C. 3, 9 D. 3, 5
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Lesson Quiz for Student Response Systems
2. Tell whether 360 is divisible by 2, 3, 4, 5,
6, 9, and 10. A. 2, 3, 4, 5, 6, 9, 10 B. 5, 10
C. 2, 4 D. 3, 6, 9
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Lesson Quiz for Student Response Systems
3. Tell whether 448 is divisible by 2, 3, 4, 5,
6, 9, and 10. A. 2, 3, 4, 5, 6, 9, 10 B. 5, 9
C. 2, 4 D. 5, 6, 9
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Lesson Quiz for Student Response Systems
4. Find the prime number. A. 52 B. 57 C. 59
D. 63
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Lesson Quiz for Student Response Systems
5. Find the composite number. A. 41 B. 61 C.
121 D. 131