Harvest Recipe Fractions

Overview

Lesson 8 of 10 in Fraction Detectives in Action. Students use harvest and recipe contexts to add and subtract fractions with the same denominator, staying within one whole. The lesson is planned for 18 students working in pairs and can be extended to 22 students by forming 9–11 pairs.

Learning intentions

• WALT add fractions with the same denominator within one whole.
• WALT subtract fractions with the same denominator within one whole.
• WALT use models to explain our fraction thinking.
• WALT connect fractions to sharing, measuring and rural harvest situations.

Success criteria

• I can identify equal-sized parts using a fraction strip or measuring model.
• I can keep the denominator unchanged.
• I can combine or subtract the numerators.
• I can write an equation and model my thinking.

Curriculum links

• Number: recognise, represent, compare and use fractions as equal parts of a whole.
• Number operations: add and subtract fractions with the same denominator in familiar contexts.
• Mathematical communication: use materials, drawings, words and equations to explain strategies.
• Competencies: thinking; using language, symbols and texts; managing self; relating to others.

Lesson structure (60 minutes)

1. 0–7 minutes – Harvest hook and revisit

Open with the harvest hook and learning intention slides. Show a picture idea of a full produce crate divided into eight equal sections and ask: “If we collect 2/8 in the morning and 3/8 in the afternoon, how much do we have altogether?” Students turn and talk, then share what the denominator and numerator tell us.

Read the WALT and success criteria aloud. Briefly revisit that the denominator names the equal parts and the numerator counts the parts.

2. 7–17 minutes – Teacher modelling

Use a large fraction strip and model 2/8 + 3/8. Place the strips together, count five eighths and record:

2/8 + 3/8 = 5/8

Then model 7/10 − 2/10 using a measuring-tank image or strip. Explicitly state: “The parts are still tenths, so the denominator stays 10. We subtract the numerators: 7 − 2 = 5.” Display the worked examples in the modelling and worked-example slides.

3. 17–22 minutes – Guided check

Give each pair a fraction strip or equivalent fraction model. Work through 1/6 + 2/6 and 5/8 − 2/8 together. Students show the answer with their strips before writing it on mini-whiteboards.

Ask: “What stayed the same? What changed? How does the model prove the equation?” Correct the common error of adding or subtracting denominators.

4. 22–42 minutes – Pair investigation: harvest recipes

Place pairs with the fraction wall and strip cards and distribute the Harvest Recipe Fractions worksheet. Pairs solve the rural harvest problems using strips, produce baskets and measuring cups or drawings. Suggested problems include:

• 2/8 of a crate of apples plus 3/8.
• 4/6 of a tray of kūmara minus 1/6.
• 3/10 of a tank plus 4/10.
• 7/10 of a tank minus 2/10.
• 5/8 of a basket plus 2/8.

For each problem, students build or draw the model, write the equation and explain their answer to their partner. Remind them that answers must not be more than one whole.

Circulate and ask: “How many equal parts are there? What does the numerator count? Why has the denominator stayed the same?”

5. 42–53 minutes – Explain and compare

Pairs choose one solution to present using the model and equation. Use the partner-share and discussion slides to show sentence frames:

• “Our whole was divided into ___ equal parts.”
• “We combined/took away ___ parts.”
• “The denominator stayed ___ because…”
• “Our equation is…”

Invite two pairs to explain different representations. The class checks whether the model, words and equation agree.

6. 53–60 minutes – Exit assessment and reflection

Return to the plenary and exit-question slide. Students independently complete the final worksheet question: 6/8 − 3/8, showing a model and equation. Ask students to circle the success criterion they feel most confident about and tell a partner one strategy they used.

Resources

• the harvest fractions slide deck
• the Harvest Recipe Fractions worksheet
• the fraction wall and strip cards
• Fraction strips or paper strips, ideally in eighths and tenths
• Small baskets, bowls or counters to represent produce
• Measuring cups or clear containers marked with equal sections
• Mini-whiteboards and pens
• Pencils, crayons and highlighters
• Prepared rural harvest problem cards or teacher-read problems

Assessment

• Listen for correct use of “numerator”, “denominator”, “equal parts” and “whole” during partner explanations.
• Check models and equations for accurate addition or subtraction of numerators and an unchanged denominator.
• Collect the final worksheet question to identify students needing further practice before lesson 9.

Differentiation

• Support: begin with unit fractions such as 1/6 + 2/6; use highlighted operation words, worked examples and concrete strips before recording equations.
• Support: read problems aloud, offer audio instructions, use dyslexia-friendly sans-serif print, generous spacing, short lines and colour-coded numerators and denominators.
• Support: pair students strategically and provide a teacher-led group using one problem at a time. Students may explain orally or draw instead of writing full sentences.
• Extension: students write two-step harvest problems, ensuring the result remains within one whole, then swap with a partner to solve, model and check.