6.13 Small Group · Group 1
Second Practice Form · Re-Teach, Homework or Retake · Same Standard, New Problems
Prime Factorization · Prime number · Procedural Fluency · Reasoning & Critique
- Prime factorization means writing a number as a product of prime numbers only. A prime number can be divided only by 1 and itself, like 2, 3, 5, and 7. We'll walk through a worked example, try one together, then you'll try a few with hints right there when you need them.
- I want the prime factorization of 60. I start by splitting it: 60 = 6 × 10.
- 6 is not prime, so I break it: 6 = 2 × 3. Both 2 and 3 are prime, so I stop those branches.
- 10 is not prime, so I break it: 10 = 2 × 5. Both 2 and 5 are prime, so I stop.
- Now every factor is prime: 60 = 2 × 2 × 3 × 5.
- Using exponents, I write it as 2² × 3 × 5. I check: 2 × 2 × 3 × 5 = 60. Correct.
- Prime Factorization (Factorización prima) — Writing a whole number as a product of only prime numbers.
- Prime number (Número primo) — A number bigger than 1 that you can only divide by 1 and itself.
- Composite number (Número compuesto) — A number bigger than 1 that you can divide by more than just 1 and itself.
- Factor (Factor) — A factor of a whole number divides it evenly, with no remainder. For example, 3 is a factor of 12 because 12 ÷ 3 = 4.
- Factor tree (Árbol de factores) — A picture that splits a number into its prime numbers, step by step.
- Exponent (Exponente) — A small number that tells how many times to multiply a number by itself.
- A common mistake in Prime Factorization is stopping the factor tree too soon — leaving a composite number like 4, 6, 8, or 9 in the final answer instead of continuing to split it. For example, writing 20 = 4 × 5 as the prime factorization (4 is composite) instead of finishing with 20 = 2 × 2 × 5. Before you submit, check every number in your final answer: if any factor can still be broken into smaller factors, the tree isn't finished yet.
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1 MULTIPLE CHOICE
Two students found different factor trees for 60. Student A started with 2 × 30. Student B started with 6 × 10. Which statement is true?
- ABoth get the same prime factorization: 2 × 2 × 3 × 5
- BOnly Student A gets the correct prime factorization
- COnly Student B gets the correct prime factorization
- DThey will get different prime factorizations
✏️ Workspace & Solution Steps
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2 MULTIPLE CHOICEFactor Tree for 90
The first lock panel shows 90. What is the prime factorization of 90?
- A2 × 3 × 3 × 5
- B2 × 45
- C9 × 10
- D3 × 30
✏️ Workspace & Solution Steps -
3 MULTIPLE CHOICE
The second panel needs a number whose prime factorization is 2² × 3². Which number unlocks it?
- A36
- B24
- C12
- D18
✏️ Workspace & Solution Steps -
4 MULTIPLE CHOICEFactor Tree for 78
The final lock asks for the prime factorization of 78 written as a product of primes. Which is correct?
- A2 × 3 × 13
- B2 × 39
- C3 × 26
- D6 × 13
✏️ Workspace & Solution Steps
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5 ERROR ANALYSIS
Spot the Common Mistake
- 1Find the prime factorization of 20:Start: 20
- 2First split:20 = 4 × 5
- 3Check each factor:5 is prime, so that branch is done.
- 4Final answer:20 = 4 × 5
Which step contains the error? Explain the mathematical misconception and write the correct calculation below.
✏️ Corrected Mathematical Work & Explanation -
6 ERROR ANALYSIS
Level 2 Extension — Fix the Broken Factor Tree
- 1Find prime factorization of 96:Start: 96
- 2First split:96 = 8 × 12
- 3Break down 8:8 = 2 × 2 × 2
- 4Break down 12:12 = 2 × 6
- 5Final answer:96 = 2 × 2 × 2 × 2 × 6
Which step contains the error? Explain the mathematical misconception and write the correct calculation below.
✏️ Corrected Mathematical Work & Explanation
Writing Task: Justify why your mathematical solution is accurate and complete.