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/Volumes/ju102/HCSC007/HCSC_indd%0/NL_indd/Chap_G5_11
Name
Lesson 11.8
Prime Factorization
Secret Code
Freddy and his friends write their names in code. Each
friend’s name is represented by a number. To identify the
friend in a message, you must find the prime factorization
of the number. Freddy gets a message from 45. Who is the
message from?
Freddy ⫽ 2 ⫻ 3 ⫻ 5
Judy ⫽ 2 ⫻ 2 ⫻ 3 ⫻ 7
Dan ⫽ 3 ⫻ 3 ⫻ 5
Camilla ⫽ 2 ⫻ 3 ⫻ 5 ⫻ 5
1. What are you asked to find?
2. What do you need to do in order to identify the friend?
3. What kind of diagram can you make to solve the problem?
4. Complete the factor tree.
45
⫻
⫻
5
⫻
5. Who is Freddy’s message from?
USE DATA For 6–7, use the secret code at the top of the page.
6. Dan sends a message to 84. Who does
Dan send a message to?
7. Dan lives next door to 150. Who does
Dan live next door to?
8. Challenge Marta is thinking of a number. The prime factorization of the number is the
first eight primes, each used as a factor exactly once. Write the prime factorization and
the number.
PS72
Problem Solving
© Harcourt • Grade 5
MXENL08AWK5X_PS_C11_L08.indd Page 72 6/1/07 6:33:42 PM elhi
/Volumes/ju102/HCSC007/HCSC_indd%0/NL_indd/Chap_G5_11
Name
Lesson 11.8
Prime Factorization
Secret Code
Freddy ⫽ 2 ⫻ 3 ⫻ 5
Judy ⫽ 2 ⫻ 2 ⫻ 3 ⫻ 7
Dan ⫽ 3 ⫻ 3 ⫻ 5
Camilla ⫽ 2 ⫻ 3 ⫻ 5 ⫻ 5
Freddy and his friends write their names in code. Each
friend’s name is represented by a number. To identify the
friend in a message, you must find the prime factorization
of the number. Freddy gets a message from 45. Who is the
message from?
1. What are you asked to find?
who Freddy gets a message from.
2. What do you need to do in order to identify the friend?
Find the prime factorization of 45, then find the
friend who is represented by that prime factorization.
3. What kind of diagram can you make to solve the problem?
a factor tree
4. Complete the factor tree.
45
9
3
⫻
3
⫻
5
⫻
5
Dan
5. Who is Freddy’s message from?
USE DATA For 6–7, use the secret code at the top of the page.
6. Dan sends a message to 84. Who does
Dan send a message to?
7. Dan lives next door to 150. Who does
Dan live next door to?
Judy
Camilla
8. Challenge Marta is thinking of a number. The prime factorization of the number is the
first eight primes, each used as a factor exactly once. Write the prime factorization and
the number.
2 ⫻ 3 ⫻ 5 ⫻ 7 ⫻ 11 ⫻ 13 ⫻ 17 ⫻ 19; 9,699,690
PS72
Problem Solving
© Harcourt • Grade 5