Recipes for Ratio

Unit Overview

Unit: Rati-O-Matic Adventures
Lesson Number: 10 of 10
Year Group: Year 6
Duration: 30 minutes
Class Size: 30 students
Curriculum Reference:

• Mathematics – Year 6 – Number: Ratio and Proportion
• National Curriculum for England (2014)
• Key objectives: Pupils solve problems involving the relative sizes of two quantities where missing values can be found by using integer multiplication and division facts, including scaling recipes.

---

Learning Objectives

By the end of this lesson, pupils will be able to:

• Apply their understanding of ratio to real-life contexts, specifically cooking recipes.
• Adjust ingredient quantities in recipes using ratios to scale quantities up or down.
• Solve problems involving the scaling of ingredients while maintaining correct proportions.

Curriculum links

• Solve problems involving the relative sizes of two quantities where missing values can be found by using integer multiplication and division facts. (NC Maths Y6)
• Use ratio and proportion to solve problems, including scaling simple recipes. (NC Maths Y6)

---

Success Criteria

• I can explain what a ratio is and how it applies to ingredients in a recipe.
• I can calculate new ingredient quantities when a recipe is scaled up or down.
• I can check my calculations to ensure the ratios remain consistent.

---

Resources

• Whiteboard and pens
• Printed copies of a simple recipe (e.g., pancake recipe) with ingredient quantities in ratios
• Worksheet: "Scaling Recipes" with varied ratios and ingredient quantities
• Measuring jugs, scales or virtual measuring tools (optional for demonstration)
• Calculators (optional, for checking work)

---

Lesson Structure

1. Starter (5 minutes) - Engage and Recap

• Begin with a quick mental warm-up: Write a ratio on the board (e.g., 2:3) and ask pupils to write the equivalent ratios (4:6, 6:9).
• Briefly recap key vocabulary: ratio, scale up, scale down, ingredients, proportion.
• Recap from the previous lessons in the unit, discussing how ratios compare quantities.
• Pose a question: “If a pancake recipe calls for 2 cups of flour and 3 eggs (a ratio of 2:3), how would you change the ingredients if you only want to make half the amount?”

2. Main Activity (20 minutes) - Recipe Scaling Challenge

• Distribute the printed recipe and worksheets. The recipe will have ingredients listed in ratio form (e.g., 2:3:1 for flour:sugar:milk).

• Explain how to scale the recipe up or down using multiplication or division with ratios; model one example on the board.

• In pairs, pupils choose one of three recipe scaling tasks:

  1. Making half the original recipe
  2. Doubling the recipe
  3. Tripling the recipe

• Pupils calculate new ingredient quantities, writing their answers on the worksheet.

• Circulate to support, asking probing questions (“How did you find the new amount for sugar?” “Does the ratio still match?”)

• Optional extension: Challenge pupils to create their own simple recipe using ratios and then swap with a partner to scale it.

3. Plenary (5 minutes) - Discuss and Reflect

• Invite a few pairs to share their scaled recipes and explain their method.
• Ask the class: “Why is it important to keep the ratio when scaling a recipe?”
• Recap the key concept: In ratios, all quantities must be adjusted proportionally for the end result to be correct.
• Quick formative assessment: Show a ratio and ask pupils to write scaled quantities on mini whiteboards for instant feedback.

---

Assessment and Differentiation

Assessment

• Formative assessment through questioning during pair work and plenary.
• Worksheets checked for accuracy in ratio scaling calculations.
• Informal assessment of reasoning via explanations shared at plenary.

Differentiation

• Support: Provide concrete measuring tools for pupils struggling with abstract calculation. Use visual aids like bar models to represent ratios.
• Challenge: Provide recipes with three or more ingredients and ask pupils to scale by non-integer factors (e.g., 1.5 times or one third).
• Extension task: Create a ratio word problem involving recipes for independent or homework.

---

Cross-Curricular Links

• Science: Discuss changes in materials when ingredients are scaled – how chemical reactions depend on proportions.
• Literacy: Encourage precise language use when explaining ratios and steps in recipe scaling.
• Cooking & DT: Opportunity for practical application if resources/time allow (future lessons or club activities).

---

Teacher Notes and Tips

• Emphasise practical, everyday use of ratios to increase engagement.
• Use concrete scenarios pupils love such as cooking or baking.
• Reinforce vocabulary explicitly to build mathematical language.
• Keep the lesson fast-paced due to short time allocation; use clear, concise explanations.
• Encourage pupils to check answers by comparing scaled ratios visually or numerically.
• Prepare to gently correct common misconceptions, such as adding instead of multiplying ratios.

---

This final lesson consolidates ratio understanding through a hands-on, real-world context, supporting pupils to become confident problem solvers in line with the National Curriculum’s focus on applying mathematical knowledge practically.