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Factor tree worksheet for practicing prime factorization with visual tree diagrams.

Factor tree worksheet with prime factorization problems, showing numbers to be broken down into prime factors using tree diagrams.

Factor tree worksheet with prime factorization problems, showing numbers to be broken down into prime factors using tree diagrams.

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Show Answer Key & Explanations Step-by-step solution for: Prime Factorization Worksheet page
Let’s solve each factor tree step by step. Remember: a factor tree breaks down a number into its prime factors — numbers that can only be divided by 1 and themselves (like 2, 3, 5, 7, etc.). We multiply all the primes at the bottom to get back the original number.

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Problem 1: 35

We start with 35. What two numbers multiply to 35?
→ 5 × 7 = 35
Both 5 and 7 are prime → stop here.
So: 35 = 5 × 7

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Problem 2: 14

Start with 14.
→ 2 × 7 = 14
Both 2 and 7 are prime → done.
So: 14 = 2 × 7

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Problem 3: 33

Start with 33.
→ 3 × 11 = 33
Both 3 and 11 are prime → done.
So: 33 = 3 × 11

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Problem 4: 12

Start with 12. The tree shows it splits into ? and 6.
What times 6 equals 12? → 2 × 6 = 12
Now break down 6: 6 = 2 × 3 (both prime)
So full breakdown: 12 = 2 × 2 × 3
Answer line says: 12 = _ × _ × _ → fill in: 2 × 2 × 3

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Problem 5: 30

Tree shows 30 splits into ? and 15.
What times 15 is 30? → 2 × 15 = 30
Break down 15: 15 = 3 × 5 (both prime)
So: 30 = 2 × 3 × 5
Answer line: 30 = _ × _ × _2 × 3 × 5

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Problem 6: 27

Tree shows 27 splits into ? and 9.
What times 9 is 27? → 3 × 9 = 27
Break down 9: 9 = 3 × 3 (both prime)
So: 27 = 3 × 3 × 3
Answer line: 27 = _ × _ × _3 × 3 × 3

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Problem 7: 20

Tree shows 20 splits into ? and ?. Let’s pick easy factors: 4 × 5 = 20
But 4 is not prime → break 4 into 2 × 2
So: 20 = 2 × 2 × 5
Answer line: 20 = _ × _ × _2 × 2 × 5

*(Note: You could also do 20 = 2 × 10, then 10 = 2 × 5 → same result)*

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Problem 8: 28

Tree shows 28 splits into ? and ?. Let’s use 4 × 7 = 28
Break 4 into 2 × 2
So: 28 = 2 × 2 × 7
Answer line: 28 = _ × _ × _2 × 2 × 7

*(Alternatively: 28 = 2 × 14 → 14 = 2 × 7 → same answer)*

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Problem 9: 45

Tree shows 45 splits into ? and ?. Try 5 × 9 = 45
Break 9 into 3 × 3
So: 45 = 5 × 3 × 3 → or written as 3 × 3 × 5
Answer line: 45 = _ × _ × _3 × 3 × 5

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All problems solved! Now let’s write the final answers clearly for each problem.

Final Answer:
1) 35 = 5 × 7
2) 14 = 2 × 7
3) 33 = 3 × 11
4) 12 = 2 × 2 × 3
5) 30 = 2 × 3 × 5
6) 27 = 3 × 3 × 3
7) 20 = 2 × 2 × 5
8) 28 = 2 × 2 × 7
9) 45 = 3 × 3 × 5
Parent Tip: Review the logic above to help your child master the concept of prime factorization worksheet.
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