Let's solve each of the factor trees in
Section A step by step, finding the
prime factor decomposition of each number and expressing it in
index notation.
We'll follow the same method as shown in the example:
---
🔹 1. 36
Start with 36.
- 36 = 2 × 18 → 2 is prime (blue), 18 is not (orange)
- 18 = 2 × 9 → 2 is prime, 9 is not
- 9 = 3 × 3 → both are prime
So:
```
36
/ \
2 18
/ \
2 9
/ \
3 3
```
Prime factors: 2, 2, 3, 3
→ $ 36 = 2^2 \times 3^2 $
✔ Answer: $ 36 = 2^2 \times 3^2 $
---
🔹 2. 54
Start with 54.
- 54 = 2 × 27 → 2 is prime, 27 is not
- 27 = 3 × 9 → 3 is prime, 9 is not
- 9 = 3 × 3 → both prime
```
54
/ \
2 27
/ \
3 9
/ \
3 3
```
Prime factors: 2, 3, 3, 3
→ $ 54 = 2 \times 3^3 $
✔ Answer: $ 54 = 2 \times 3^3 $
---
🔹 3. 135
Start with 135.
- 135 = 5 × 27 → 5 is prime, 27 is not
- 27 = 3 × 9 → 3 is prime, 9 is not
- 9 = 3 × 3 → both prime
```
135
/ \
5 27
/ \
3 9
/ \
3 3
```
Prime factors: 5, 3, 3, 3
→ $ 135 = 3^3 \times 5 $
✔ Answer: $ 135 = 3^3 \times 5 $
---
🔹 4. 525
Start with 525.
- 525 = 5 × 105 → 5 is prime, 105 is not
- 105 = 5 × 21 → 5 is prime, 21 is not
- 21 = 3 × 7 → both prime
```
525
/ \
5 105
/ \
5 21
/ \
3 7
```
Prime factors: 5, 5, 3, 7
→ $ 525 = 3 \times 5^2 \times 7 $
✔ Answer: $ 525 = 3 \times 5^2 \times 7 $
---
🔹 5. 693
Start with 693.
- 693 = 3 × 231 → 3 is prime, 231 is not
- 231 = 3 × 77 → 3 is prime, 77 is not
- 77 = 7 × 11 → both prime
```
693
/ \
3 231
/ \
3 77
/ \
7 11
```
Prime factors: 3, 3, 7, 11
→ $ 693 = 3^2 \times 7 \times 11 $
✔ Answer: $ 693 = 3^2 \times 7 \times 11 $
---
##
✔ Final Answers:
| Number | Prime Factor Decomposition (Index Notation) |
|--------|---------------------------------------------|
| 36 | $ 2^2 \times 3^2 $ |
| 54 | $ 2 \times 3^3 $ |
| 135 | $ 3^3 \times 5 $ |
| 525 | $ 3 \times 5^2 \times 7 $ |
| 693 | $ 3^2 \times 7 \times 11 $ |
---
📌 Summary of How to Solve:
1. Start with the number at the top.
2. Break it into two factors: one prime (blue circle), one composite (orange).
3. Keep breaking down the composite numbers until all branches end in
prime numbers.
4. List all the
prime numbers at the bottom.
5. Write them in
index form (e.g., $ 2^4 $).
Let me know if you'd like this filled in on the worksheet format!
Parent Tip: Review the logic above to help your child master the concept of factor tree worksheets.