Fraction division: To divide a fraction by a whole number, multiply the fraction by the reciprocal of the whole number: \( \frac{a}{b} \div n = \frac{a}{b} \times \frac{1}{n} \)
- Identify the operation needed (division for sharing equally)
- Set up the division: 3/4 ÷ 6
- Convert division to multiplication: 3/4 × 1/6
- Perform the multiplication: (3×1)/(4×6) = 3/24 = 1/8
- For the second part, multiply by 1/2: 1/8 × 1/2 = 1/16
3/4 ÷ 6 = 3/4 × 1/6 = 3/24 = 1/8 of the batch per friend
1/2 of their share = 1/2 × 1/8 = 1/16 of the original batch
If each friend eats 1/16 of the batch, 6 friends eat 6 × 1/16 = 6/16 = 3/8 of the batch
This is less than the original 3/4, which makes sense.
Each friend gets 1/8 of the batch and eats 1/16 of the original batch
• Division by whole number: Multiply by reciprocal
• Fraction multiplication: Multiply numerators and denominators separately
• Word problem interpretation: "divide equally" indicates division, "of" indicates multiplication
Rate calculation: To find the daily rate, divide the total amount by the number of days.
5/6 of the book in 5 days = 5/6 ÷ 5 = 5/6 × 1/5 = 5/30 = 1/6 of the book per day
2 books ÷ daily rate (1/6 book per day) = 2 ÷ 1/6 = 2 × 6/1 = 12 days
At 1/6 per day for 12 days = 12 × 1/6 = 2 books ✓
The student reads 1/6 of the book per day, and it takes 12 days to read 2 books
• Rate calculation: Total amount ÷ Time period
• Division by fraction: Multiply by reciprocal
• Verification: Check that the rate multiplied by time equals the total
Sequential operations: When dividing a fraction by a whole number, then multiplying the result by another fraction, perform operations in sequence.
7/8 ÷ 4 = 7/8 × 1/4 = 7/32 of the container per student
2/3 of their share = 2/3 × 7/32 = 14/96 = 7/48 of the original container
4 students × 7/48 each = 28/48 = 7/12 of the container
Started with 7/8, used 7/12: 7/8 - 7/12 = 21/24 - 14/24 = 7/24 remaining
Each student uses 7/48 of the original container, and 7/24 of the paint remains unused
• Division by whole number: Multiply by reciprocal
• Fraction multiplication: Multiply numerators and denominators separately
• Subtraction with fractions: Need common denominators
Fraction multiplication: Multiply numerators together and denominators together. Used when finding part of a part.
Fraction division: Multiply by the reciprocal of the divisor. Used when sharing equally or finding how many times one quantity fits into another.
Reciprocal: The multiplicative inverse of a number (flipping the numerator and denominator).
- Read the problem carefully: Identify if it involves sharing/equal groups (division) or finding part of a part (multiplication)
- Identify the operation: Look for keywords like "divide", "share", "each" (division) vs "of", "times", "product" (multiplication)
- Set up the calculation: Write the appropriate operation
- Perform the operation: Apply multiplication or division rules
- Simplify the result: Reduce to lowest terms if possible
- Check your answer: Verify if it makes sense in the context of the problem
Division for grouping: To find how many equal-sized portions fit into a total amount, divide the total by the size of each portion.
3/5 ÷ 1/10 = 3/5 × 10/1 = 30/5 = 6 full cups
4/5 of 6 cups = 4/5 × 6 = 24/5 = 4.8 cups, but since we only have full cups, 4/5 of 6 = 24/5 = 4.8, so 4 full cups
4 cups × 1/10 gallon per cup = 4/10 = 2/5 gallon
6 full cups can be filled, and 2/5 gallon of water was consumed
• Division for grouping: Total ÷ Size per group = Number of groups
• Fraction division: Multiply by reciprocal of divisor
• Fraction multiplication: Multiply numerators and denominators separately
Adjusting rates: When changing the time period but keeping the total amount constant, divide the remaining amount by the remaining time.
9 days × 2/3 mile/day = 18/3 = 6 miles total
6 days × 2/3 mile/day = 12/3 = 4 miles completed
Total - Completed = 6 - 4 = 2 miles remaining
New plan is 12 days total, 6 already completed = 6 remaining days
Remaining distance ÷ Remaining days = 2 ÷ 6 = 2/6 = 1/3 mile per day
The student should walk 1/3 mile each day for the remaining 6 days
• Multiplication for totals: Rate × Time = Total
• Subtraction for remaining: Total - Completed = Remaining
• Division for new rate: Remaining ÷ Time = New Rate
Fraction multiplication: To multiply fractions, multiply the numerators together and the denominators together. This is used when finding a part of a part.
Fraction division: To divide fractions, multiply the first fraction by the reciprocal of the second fraction. This is used when sharing equally or finding how many times one quantity fits into another.
Reciprocal: The reciprocal of a fraction a/b is b/a. The reciprocal of a whole number n is 1/n.
- Problem analysis: Determine whether the situation calls for multiplication or division
- Operation identification: Look for key words - "of", "times" suggest multiplication; "divide", "share", "each", "per" suggest division
- Setup calculation: Write the appropriate mathematical expression
- Perform operation: Apply multiplication or division rules correctly
- Simplify result: Reduce to lowest terms if possible
- Verify answer: Check if the answer makes sense in the problem context
• Multiplication rule: \(\frac{a}{b} \times \frac{c}{d} = \frac{a \times c}{b \times d}\)
• Division rule: \(\frac{a}{b} \div \frac{c}{d} = \frac{a}{b} \times \frac{d}{c}\)
• Division by whole number: \(\frac{a}{b} \div n = \frac{a}{b} \times \frac{1}{n}\)
• Word problem keywords: "of" → multiplication, "per", "each", "out of" → division
• Verification: Check that multiplication and division operations make logical sense in context
Worksheet Success Guide
1. Multiply numerators (top numbers)
2. Multiply denominators (bottom numbers)
3. Simplify if possible
1. Keep first fraction
2. Change ÷ to ×
3. Flip second fraction
4. Multiply as usual
• Label each step clearly
• Box your final answers
• Show all work
• Check reasonableness