K-5 friendly lesson

One small step at a time.Read the idea, try the activity, and celebrate each win as you go.

Understand factors and factor pairs

Factors are the numbers you multiply together to get another number! Finding factors is like solving a puzzle - which numbers fit together perfectly?

Do this: Read the concept below, then try the quiz or activity.

Lesson 51 of 202

Concept

Factors are building blocks of numbers!

🎯 What Are Factors? Factors of a number are all the whole numbers that divide into it evenly (with no remainder).

Example: Factors of 12 Which numbers divide evenly into 12? • 12 ÷ 1 = 12 ✓ • 12 ÷ 2 = 6 ✓ • 12 ÷ 3 = 4 ✓ • 12 ÷ 4 = 3 ✓ • 12 ÷ 5 = 2.4 ✗ (not a whole number) • 12 ÷ 6 = 2 ✓ • 12 ÷ 12 = 1 ✓

Factors of 12: 1, 2, 3, 4, 6, 12

💡 Factor Pairs: Factor pairs are two numbers that multiply to give you the original number.

Factor pairs of 12: • 1 × 12 = 12 • 2 × 6 = 12 • 3 × 4 = 12

Notice: Each factor appears in a pair!

🔍 Finding Factor Pairs Systematically:

For 24: • Start with 1: 1 × 24 = 24 ✓ • Try 2: 2 × 12 = 24 ✓ • Try 3: 3 × 8 = 24 ✓ • Try 4: 4 × 6 = 24 ✓ • Try 5: Doesn't work evenly • Stop when numbers repeat!

Factor pairs of 24: (1,24), (2,12), (3,8), (4,6) All factors of 24: 1, 2, 3, 4, 6, 8, 12, 24

🌟 Special Facts: • 1 is a factor of EVERY number • Every number is a factor of itself • Even numbers always have 2 as a factor • Numbers with an odd number of factors are perfect squares!

🎨 Array Model: You can show factor pairs with arrays!

12 can be arranged as:
• 1 row of 12: ●●●●●●●●●●●●
• 2 rows of 6: ●●●●●●
              ●●●●●●
• 3 rows of 4: ●●●●
              ●●●●
              ●●●●

Try it

Practice finding factors and factor pairs!

📝 List All Factors: 1. Find all factors of 18 2. Find all factors of 20 3. Find all factors of 30 4. Find all factors of 16

🔢 Find Factor Pairs: 5. List all factor pairs of 24 6. List all factor pairs of 36 7. List all factor pairs of 28

🎯 True or False: 8. 4 is a factor of 32 (True/False) 9. 7 is a factor of 56 (True/False) 10. 5 is a factor of 27 (True/False)

🎨 Missing Factor: 11. 3 × ___ = 24 (Find the missing factor) 12. ___ × 7 = 42 13. 8 × ___ = 64

🏆 Word Problems: 14. You have 18 chairs to arrange in equal rows. What are all the possible arrangements? (Use factor pairs!)

15. A rectangle has an area of 36 square units. What are all the possible whole number dimensions?

💪 Challenge: 16. What number less than 30 has the most factors? 17. Name a number between 10 and 20 that has exactly 4 factors.

Complete & Continue →