Review of Fractions - Mr. J's Math Class

Overview

• Quick refresher on adding, subtracting, multiplying, and dividing fractions.
• For more detailed explanations, refer to linked videos in the description.

1. Adding Fractions

Example: 5/8 + 1/3

• Find a common denominator: Least common multiple of 8 (denominator) and 3 (denominator) is 24.
• Convert fractions to have a common denominator:
  • 5/8: Multiply both numerator and denominator by 3 → 5/8 = 15/24
  • 1/3: Multiply both numerator and denominator by 8 → 1/3 = 8/24
• Add numerators: 15 + 8 = 23
• Simplified answer: 23/24 (already in simplest form)

2. Subtracting Fractions

Example: 1/2 - 2/5

• Find a common denominator: Least common multiple of 2 and 5 is 10.
• Convert fractions to have a common denominator:
  • 1/2: Multiply both numerator and denominator by 5 → 1/2 = 5/10
  • 2/5: Multiply both numerator and denominator by 2 → 2/5 = 4/10
• Subtract numerators: 5 - 4 = 1
• Simplified answer: 1/10 (already in simplest form)

3. Multiplying Fractions

Example: 2/8 * 1/4*

• No need for a common denominator.
• Multiply numerators and denominators:
  • 2 * 1 = 2
  • 8 * 4 = 32
• Simplify the fraction: 2/32
  • Divide both numerator and denominator by their greatest common factor (2).
  • Simplified fraction: 1/16

4. Dividing Fractions

Example: 5/6 ÷ 2/7

• Keep, Switch, Flip:
  • Keep the first fraction: 5/6
  • Switch the division symbol to multiplication
  • Flip the second fraction: 7/2 (reciprocal)
• Multiply fractions: 5/6 * 7/2
  • 5 * 7 = 35
  • 6 * 2 = 12
• Convert improper fraction to mixed number:
  • 35/12
  • 35 divided by 12: quotient = 2, remainder = 11
  • Mixed number: 2 11/12 (already in simplest form)*

Conclusion

• Brief review of fraction operations.
• For more examples and detailed instruction, refer to additional videos linked in the description.