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👩‍🍳 Master Chef Kitchen

Multiplying & Dividing Fractions • Unit 2

Step 1 of 5

Step 1 — Welcome to the Kitchen

You are the new head chef at Le Fraction Bistro. Every recipe uses fractions. Finish all 5 steps to earn your Chef Certificate!

1

Sign in, Chef

Type your name so we can put it on your certificate.

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What you will do

  • Multiply fractions to grow a recipe bigger.
  • Divide fractions to split food into servings.
  • Change mixed numbers into improper fractions.
  • Solve real cooking word problems.
🪜 You can do this! Go one small step at a time. Use the green "How to do it" boxes, the yellow examples, and the 💡 Hint buttons whenever you need them.
🌟 Push yourself After each table, answer the "Explain your thinking" prompt and try the ⭐ Challenge boxes with bigger numbers.

Step 2 — Pantry Lab (Learn the Moves)

Read these three quick tools. You will use them in every step.

Tool 1 · Multiply fractions

How to do it: Multiply the top numbers. Multiply the bottom numbers. Then simplify.
Example: 2/3 × 3/4 = (2×3)/(3×4) = 6/12 = 1/2

Tool 2 · Divide fractions — "Keep, Change, Flip"

How to do it: Keep the first fraction. Change ÷ into ×. Flip the second fraction (its reciprocal). Then multiply.
Example: 3/4 ÷ 1/2 = 3/4 × 2/1 = 6/4 = 1 1/2

Tool 3 · Mixed number → improper fraction

How to do it: Multiply the whole number by the bottom. Add the top. Keep the same bottom.
Example: 2 1/3 = (2×3 + 1)/3 = 7/3

Fraction strips (a picture to help)

One whole can be split into equal parts:

1 whole
1/2
1/2
1/3
1/3
1/3
1/4
1/4
1/4
1/4
2.1

Warm-up: Change to improper fractions

Each cup below shows a mixed number of cups. Change each one into an improper fraction so we can scale the recipe.

Example: 2 1/2 → (2×2 + 1)/2 = 5/2
Ingredient Mixed number Your improper fraction
🌾 Flour 2 1/2 cups
🍯 Sugar 1 3/4 cups
🥛 Milk 3 2/3 cups
🧈 Butter 1 1/8 cups
For 2 1/2: 2 × 2 = 4, then 4 + 1 = 5. Bottom stays 2, so the answer is 5/2. Do the same for the others.

Step 3 — Multiply to Scale Recipes

Multiplying makes a recipe a different size. Use Tool 1 from Step 2.

3.1

Half-batch cake

A customer wants half of our cake recipe. Multiply each amount by 1/2. Then simplify if you can.

How to do it: top × top, bottom × bottom. Example: 3/4 × 1/2 = 3/8.
Ingredient Full recipe × 1/2 = Simplified
🌾 Flour 3/4 cup
🍫 Cocoa 2/3 cup
🧈 Butter 5/8 cup
🥛 Cream 4/5 cup
Sentence starter To multiply fractions, I… multiply the tops multiply the bottoms then simplify
For 3/4 × 1/2: top = 3×1 = 3, bottom = 4×2 = 8. So the answer is 3/8.
⭐ Challenge: Triple batch A banquet needs 3 times the recipe. Multiply each amount by 3 and write any improper answer as a mixed number.
3.2

Party-size pasta

The Garden Pasta serves 4. A party of 6 is coming. Multiply each amount by 6/4 (which is the same as 3/2).

Ingredient Serves 4 × 3/2 = Simplified
🍝 Pasta 2/3 lb
🧄 Garlic 3/4 tbsp
🫒 Olive oil 1/3 cup
🧀 Cheese 5/8 cup
For 2/3 × 3/2: top = 2×3 = 6, bottom = 3×2 = 6, so 6/6 = 1. One pound of pasta!
3.3

Design your own dish

Make up a recipe with at least 5 ingredients that use fractions. Then double it (multiply each amount by 2) for a bigger group.

⭐ Challenge: Explain your reasoning

Step 4 — Divide into Servings

Dividing tells you how many servings fit in the food you have. Use Tool 2: Keep, Change, Flip.

4.1

How many servings?

Divide the total amount by the amount in one serving. First write the division. Then find the number of servings.

Example: 3/4 ÷ 1/4 = 3/4 × 4/1 = 12/4 = 3 servings.
Food Total Per serving Division Servings
🎂 Batter 3/4 cup 1/8 cup
🍕 Dough 2/3 lb 1/6 lb
🧃 Juice 5/6 gal 1/3 gal
🍰 Frosting 7/8 cup 1/4 cup
Word bank keepchange ÷ to × flipreciprocalmultiply
For 3/4 ÷ 1/8: Keep 3/4, change to ×, flip 1/8 to 8/1. Then 3/4 × 8/1 = 24/4 = 6 servings.
4.2

Word problems

Problem 1. The kitchen has 3 1/2 pounds of chicken. Each serving uses 2/3 pound. How many full servings can the chef make?

🪜 Steps 1) Change 3 1/2 to 7/2. 2) Keep, Change, Flip: 7/2 ÷ 2/3 = 7/2 × 3/2. 3) Multiply, then count whole servings.

Problem 2. A recipe needs 2/3 cup of oil. The chef only has a 1/4-cup scoop. How many scoops are needed?

Problem 3. The bakery uses 5/6 of a flour bag each day. They have 4 1/6 bags. How many full days will the flour last?

"How many ___ fit in ___?" means divide. Always change mixed numbers to improper fractions first.
4.3

Write your own kitchen problem

Write your own short word problem that uses dividing fractions. Then solve it.

⭐ Challenge: Teach it

Step 5 — Chef's Table (Reflect & Finish)

Rate yourself, reflect, and earn your certificate.

Rate yourself

Be honest — this helps your teacher help you.

Skill 1 · Just starting 2 · Getting there 3 · I can do it 4 · I can teach it
Multiplying fractions
Dividing fractions
Mixed numbers
Word problems

Chef's reflection

Your kitchen report

Click the button to see how much you finished.