Fractional Measurement: Using fractions to represent parts of measurement units
Mixed Numbers: Whole numbers combined with fractions (e.g., 2½)
Equivalent Fractions: Different fractions representing the same amount
Common Denominators: Same denominators needed for fraction operations
- Identify the unit: Determine the measurement type (length, weight, capacity)
- Recognize fractions: Identify whole numbers and fractional parts
- Find common denominators: When adding or subtracting fractions
- Perform operations: Add, subtract, or compare as needed
- Simplify answers: Reduce fractions when possible
Problem 2: Tom's desk is 7¾ centimeters long. His bookshelf is 5½ centimeters long. How much longer is the desk?
Problem 3: A rope measures 3¼ meters. How many centimeters is this?
Length conversion: 1 meter = 100 centimeters
Mixed number subtraction: Convert to improper fractions when needed
- Convert mixed numbers to improper fractions
- Find common denominators
- Perform the operation
- Convert back to mixed numbers if needed
- Include the correct unit in your answer
Original: 6½ cm = 13/2 cm
Used: 2¼ cm = 9/4 cm
Find common denominator: 13/2 = 26/4
Remaining: 26/4 - 9/4 = 17/4 = 4¼ cm
Answer: 4¼ cm
Desk: 7¾ cm = 31/4 cm
Bookshelf: 5½ cm = 11/2 cm = 22/4 cm
Difference: 31/4 - 22/4 = 9/4 = 2¼ cm
Answer: The desk is 2¼ cm longer
3¼ meters = 13/4 meters
13/4 × 100 = 1300/4 = 325 centimeters
Answer: 325 cm
1. 4¼ cm | 2. 2¼ cm longer | 3. 325 cm
• Mixed to improper: Whole × denominator + numerator
• Common denominators: Needed for addition/subtraction
• Conversion: 1 meter = 100 centimeters
Problem 2: Which is heavier: 2⅔ kilograms or 2¾ kilograms?
Problem 3: Mom bought 4⅓ kilograms of rice. She used 1½ kilograms. How much rice is left?
Weight conversion: 1 kilogram = 1000 grams
Fraction comparison: Find common denominators to compare
Start: 3½ kg = 7/2 kg
Eaten: 1¾ kg = 7/4 kg
Find common denominator: 7/2 = 14/4
Remaining: 14/4 - 7/4 = 7/4 = 1¾ kg
Answer: 1¾ kg
2⅔ kg = 8/3 kg and 2¾ kg = 11/4 kg
Find common denominator: 8/3 = 32/12 and 11/4 = 33/12
33/12 > 32/12, so 2¾ kg is heavier
Answer: 2¾ kilograms is heavier
Bought: 4⅓ kg = 13/3 kg
Used: 1½ kg = 3/2 kg
Find common denominator: 13/3 = 26/6 and 3/2 = 9/6
Left: 26/6 - 9/6 = 17/6 = 2⅚ kg
Answer: 2⅚ kg
1. 1¾ kg | 2. 2¾ kg is heavier | 3. 2⅚ kg
• Conversion: Mixed to improper fractions
• Common denominators: Required for fraction operations
• Comparison: Convert to same denominator for comparison
Problem 2: A jug contains 2⅔ liters of juice. Small cups that hold ⅓ liters each are filled. How many cups can be filled?
Problem 3: A container has 3¾ liters of water. How many ½-liter portions can be made?
Capacity conversion: 1 liter = 1000 milliliters
Fraction division: Multiply by reciprocal when dividing fractions
Start: 1½ L = 3/2 L
Drunk: ¾ L
Find common denominator: 3/2 = 6/4
Remaining: 6/4 - 3/4 = 3/4 L
Answer: ¾ liters
Total: 2⅔ L = 8/3 L
Each cup: ⅓ L
Number of cups: 8/3 ÷ 1/3 = 8/3 × 3/1 = 24/3 = 8 cups
Answer: 8 cups
Total: 3¾ L = 15/4 L
Portion size: ½ L
Number of portions: 15/4 ÷ 1/2 = 15/4 × 2/1 = 30/4 = 7½ portions
So 7 full portions can be made
Answer: 7 full portions
1. ¾ liters | 2. 8 cups | 3. 7 full portions
• Division of fractions: Multiply by reciprocal
• Common denominators: Needed for addition/subtraction
• Practical answers: Consider context (whole portions only)
Problem 2: Sarah practiced piano for 45 minutes. Tom practiced for 1¼ hours. How much longer did Tom practice?
Problem 3: A school event lasts 2¾ hours. How many minutes is this?
Time conversion: 1 hour = 60 minutes
Fraction of an hour: ½ hour = 30 minutes, ¼ hour = 15 minutes
Start: 2:30 PM
Duration: 1½ hours = 1 hour 30 minutes
End: 2:30 + 1:30 = 4:00 PM
Answer: 4:00 PM
Sarah: 45 minutes
Tom: 1¼ hours = 1 hour 15 minutes = 75 minutes
Difference: 75 - 45 = 30 minutes
Answer: 30 minutes longer
2¾ hours = 2 hours + ¾ hour = 2 hours + 45 minutes = 165 minutes
(2 × 60) + 45 = 120 + 45 = 165 minutes
Answer: 165 minutes
1. 4:00 PM | 2. 30 minutes longer | 3. 165 minutes
• Time addition: Add hours and minutes separately
• Fraction to minutes: ¾ hour = 45 minutes
• Conversion: 1 hour = 60 minutes
Equivalent fractions: Different fractions that represent the same value
Mixed numbers: Whole numbers combined with fractions
Improper fractions: Numerator greater than denominator
Common denominators: Same denominator needed for operations
- Identify the operation: Determine if adding, subtracting, or comparing
- Find common denominators: When denominators differ
- Perform calculations: With same denominators
- Simplify results: Reduce fractions when possible
- Convert as needed: Between mixed numbers and improper fractions
• Addition: Keep denominator, add numerators (same denominator)
• Subtraction: Keep denominator, subtract numerators (same denominator)
• Multiplication: Multiply numerators, multiply denominators
• Division: Multiply by reciprocal of divisor
• Conversion: Mixed to improper: whole × denominator + numerator
| Fraction | Decimal | Percentage | Visual Representation |
|---|---|---|---|
| ½ | 0.5 | 50% | ½ |
| ¼ | 0.25 | 25% | ¼ |
| ¾ | 0.75 | 75% | ¾ |
| ⅓ | 0.33... | 33⅓% | ⅓ |
| ⅔ | 0.66... | 66⅔% | ⅔ |
| ⅕ | 0.2 | 20% | ⅕ |