Fraction Feast Slides Fraction Feast
Multiplying Fractions in the NC Kitchen
Standard 5.NF.4-6 • Grade 5/6 Math
Our Learning Menu
Modeling
Use area models and number lines to see how fractions multiply.
Scaling
Understand how products change when we multiply by a fraction.
Real-World Math
Apply our skills to scale North Carolina recipes!
"Math is the secret ingredient in every great meal!"
Fraction × Whole Number
Problem: Each batch of NC BBQ sauce needs \( \frac{2}{3} \) cup of vinegar. How much do we need for 4 batches?
Visualizing on a Number Line
0
1
2
3
+\(\frac{2}{3}\) +\(\frac{2}{3}\) +\(\frac{2}{3}\) +\(\frac{2}{3}\)
\( 4 \times \frac{2}{3} = \frac{8}{3} = 2\frac{2}{3} \) cups
Fraction × Fraction
Finding "part of a part". Problem: \( \frac{1}{2} \) of \( \frac{3}{4} \)
Step 1: Model the 1st fraction
Shade \( \frac{3}{4} \) of the square using vertical columns.
Step 2: Model the 2nd fraction
Shade \( \frac{1}{2} \) of the square using horizontal rows.
Step 3: Count the Overlap
The area shaded BOTH ways is the product.
\(\frac{3}{4}\) columns
\(\frac{1}{2}\) row
\( \frac{1}{2} \times \frac{3}{4} = \frac{3}{8} \)
The Kitchen Shortcut
Models are great for seeing the math, but the standard algorithm is faster for big recipes!
1
Multiply Numerators
Top × Top
2
Multiply Denominators
Bottom × Bottom
3
Simplify
Reduce to lowest terms
\[ \frac{a}{b} \times \frac{c}{d} = \frac{a \times c}{b \times d} \]
Interpreting Scaling
What happens to a product when we multiply?
> 1
Multiplying by a number > 1
The product will be larger than the original. (Magnifying)
< 1
Multiplying by a number < 1
The product will be smaller than the original. (Shrinking)
= 1
Multiplying by 1
The product stays the same size . (Identity Property)
Kitchen Challenge
1
Scale the Recipe
A recipe for 1 pie calls for \( \frac{3}{4} \) lb of NC peaches. How many lbs for 6 pies?
Strategy: Whole Number × Fraction
Think: \( 6 \times \frac{3}{4} \)
2
The Secret Sauce
You have \( \frac{2}{3} \) cup of honey. You use \( \frac{1}{4} \) of it for a glaze. How much was used?
Strategy: Fraction × Fraction
Think: \( \frac{1}{4} \times \frac{2}{3} \)
Chef's Table Review
Today we mastered modeling and multiplying fractions in the North Carolina kitchen!
\( \times \) Multiply
\( \square \) Model
\( \leftrightarrow \) Scale
Ready for the Fraction Feast Challenge?
Fraction Feast Challenge Worksheet Fraction Feast Challenge
Multiplying Fractions in the North Carolina Kitchen
Name:
Date:
Part 1: The Visual Chef (Modeling)
1. Model \( \frac{2}{3} \times \frac{3}{5} \) using the area model below.
Product: ________
2. Model \( 4 \times \frac{3}{4} \) on the number line below.
0
1
2
3
4
Product: ________
Part 2: Scaling the NC Classics
3. Outer Banks Blueberry Cobbler: A single serving uses \( \frac{5}{8} \) cup of sugar. Mrs. Miller is making \( \frac{1}{2} \) of a serving for a tasting. How many cups of sugar does she need?
4. Lexington BBQ Sauce: Chef Tony makes a giant batch using 12 cups of cider vinegar. He wants to make a new batch that is \( \frac{2}{3} \) the size of the original. How many cups of vinegar will he use?
5. Sweet Potato Scaling: A standard recipe calls for \( \frac{3}{4} \) teaspoon of nutmeg. If you want to triple (\( \times 3 \)) the recipe, how many teaspoons do you need? Express your answer as a mixed number.
Part 3: EOG Skills Practice
6. Which expression is equivalent to \( 5 \times \frac{3}{8} \)?
A \( \frac{15}{8} \)
B \( \frac{15}{40} \)
C \( \frac{8}{15} \)
D \( \frac{5}{8} \)
7. Which of the following products will be GREATER than 12?
A \( 12 \times \frac{1}{2} \)
B \( 12 \times \frac{3}{4} \)
C \( 12 \times \frac{5}{4} \)
D \( 12 \times \frac{8}{8} \)
8. A rectangle has a length of \( \frac{2}{3} \) foot and a width of \( \frac{4}{5} \) foot. What is the area of the rectangle in square feet?
A \( \frac{6}{8} \)
B \( \frac{8}{15} \)
C \( \frac{2}{15} \)
D \( \frac{6}{15} \)
9. Sam has \( \frac{3}{4} \) gallon of paint. He uses \( \frac{2}{3} \) of the paint to color his doghouse. How much paint did he use?
A \( \frac{5}{7} \) gallon
B \( \frac{1}{2} \) gallon
C \( \frac{1}{4} \) gallon
D \( \frac{6}{7} \) gallon
10. Which statement about the product of \( \frac{3}{5} \times \frac{2}{3} \) is true?
A The product is greater than \( \frac{3}{5} \).
B The product is equal to \( \frac{2}{3} \).
C The product is less than \( \frac{2}{3} \).
D The product is greater than 1.
11. A hiking trail is 8 miles long. If Chloe walks \( \frac{3}{4} \) of the trail, how many miles has she walked?
Fraction Feast Answer Key Answer Key
Fraction Feast Challenge
Teacher Resource
Part 1: The Visual Chef
Model \( \frac{2}{3} \times \frac{3}{5} \)
Key: Student should shade 3 vertical columns out of 5, and 2 horizontal rows out of 3. The overlap should show 6 small boxes shaded out of 15 total.
Product: \( \frac{6}{15} \) or \( \frac{2}{5} \)
Model \( 4 \times \frac{3}{4} \)
Key: Student should show 4 jumps of \( \frac{3}{4} \) each on the number line, ending at the 3 mark.
Product: \( \frac{12}{4} \) or 3
Part 2: Scaling the NC Classics
Blueberry Cobbler (\( \frac{1}{2} \) of \( \frac{5}{8} \))
Math: \( \frac{1}{2} \times \frac{5}{8} = \frac{5}{16} \)
Answer: \( \frac{5}{16} \) cup of sugar
Lexington BBQ Sauce (\( \frac{2}{3} \) of 12)
Math: \( \frac{2}{3} \times \frac{12}{1} = \frac{24}{3} = 8 \)
Answer: 8 cups of vinegar
Sweet Potato Scaling (\( \frac{3}{4} \times 3 \))
Math: \( \frac{3}{4} \times \frac{3}{1} = \frac{9}{4} = 2\frac{1}{4} \)
Answer: \( 2\frac{1}{4} \) teaspoons
Part 3: EOG Skills Practice
A (\( \frac{15}{8} \))
C (\( 12 \times \frac{5}{4} \), because \( \frac{5}{4} > 1 \))
B (\( \frac{2 \times 4}{3 \times 5} = \frac{8}{15} \))
B (\( \frac{3}{4} \times \frac{2}{3} = \frac{6}{12} = \frac{1}{2} \))
C (Multiplying by a value \( < 1 \))
C (\( 8 \times \frac{3}{4} = 6 \))
D (\( \frac{15}{60} \) simplifies to \( \frac{1}{4} \))
B (Scaling logic: must multiply by \( > 1 \) to increase)
Grading Tips:
Partial credit is recommended for modeling questions (1 & 2) if the visual is correct but the numerical answer is wrong.
For word problems (3-5), look for the correct expression setup as well as the final answer.
Simplified answers are standard, but equivalent unsimplified fractions should be accepted unless "simplest form" is specified.
