Calculating Start and Finish Times

Overview

This session is Lesson 2 of 3 in the unit "Mastering Time Calculations" designed for Year 5 pupils (ages 9–10). Pupils will deepen their understanding of calculating start and finish times by adding and subtracting hours and minutes within practical, real-world contexts. This builds on prior knowledge of telling time and basic time intervals, aligning with the Curriculum for Wales’ Numeracy and Mathematics Area of Learning Experience (AoLE).

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Curriculum for Wales Alignment

Relevant Statements of What Matters (Year 5)

• NM3: Timing and sequencing events using different units of time helps to make sense of daily activities.
• NM4: Using mental and formal written methods to solve problems involving time supports understanding of number relationships and number operations.

Learning Area Statements (Mathematics and Numeracy)

• Select and use the most appropriate mental or written strategy to solve problems involving addition and subtraction of appropriate units of time.
• Interpret and solve time-related problems in real-life contexts.

Cross-Curricular Skills

• Numeracy: Calculate using both discrete numbers and continuous quantities (time).
• Communication: Explain reasoning systematically.
• Digital Competency: Use interactive time charts and number line apps for visualisation (optional).

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Learning Objectives

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

1. Calculate start or finish times by adding or subtracting hours and minutes.
2. Solve word problems involving time durations in hours and minutes.
3. Use visual tools like number lines and time charts to aid understanding.

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Success Criteria

Pupils can:

• Correctly calculate start or finish times in a range of scenarios.
• Explain the steps used to solve problems aloud or in writing.
• Use visual aids accurately when needed to work out time calculations.

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Resources

• Whiteboard and markers
• Individual time charts (analog clock face diagrams)
• Number line templates marked in minutes and hours
• Word problem worksheets differentiated by difficulty level
• Stopwatches or timers (optional for practical activity)
• Interactive smartboard software with clock/time tools (if available)

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Lesson Structure (45 minutes)

1. Starter (5 minutes)

• Recap previous lesson: Quick Q&A on telling time and basic time addition/subtraction.
• Pose a challenge: "If a film starts at 3:15 pm and lasts 1 hour 45 minutes, when does it finish?" Pupils volunteer answers and strategies.

2. Introduction & Modelling (10 minutes)

• Explain today’s focus: calculating start and finish times from durations.
• Use a large, visible analog clock and number line to demonstrate adding 1 hour 45 minutes to 3:15.
• Show subtraction example: “A game finished at 5:30 pm. It lasted 2 hours 20 minutes. When did it start?” Model the counting back using the number line.
• Highlight key tips: break times into hours + minutes, deal with carrying/borrowing minutes and hours separately.

3. Guided Practice (10 minutes)

• Distribute worksheets with varied word problems (examples below).
• Pupils work in pairs supported by the teacher or teaching assistant.
• Encourage use of number lines and time charts for pupils who find calculations difficult.

Sample Problems:

• A train left at 9:20 am and travelled for 2 hours 35 minutes. When did it arrive?
• A football match ended at 4:15 pm and lasted 1 hour 50 minutes. What time did it start?

4. Differentiation Strategies

• Support: Use visual aids (printed number lines, clock faces) and one-on-one guidance. Pupils physically move clock hands or use counters on number lines.
• Challenge: Pupils who finish early create their own word problems involving start and finish times, written clearly for peers to solve.

5. Independent Practice (15 minutes)

• Pupils work individually on a set of differentiated problem cards (tiered by complexity).
• Circulate to provide targeted support and assess understanding.
• Advanced learners begin creating their own problems or explain their solving method in writing.

6. Plenary & Assessment (5 minutes)

• Select a few pupils to present their solutions and reasoning aloud.
• Quick formative assessment using mini-whiteboards: teacher calls out start time and duration; pupils write finish time (or vice versa).
• Reflect on success criteria: Did everyone calculate times accurately? Who used number lines or time charts effectively?

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Differentiation Summary

Learner Group	Strategy	Resources/Support
Struggling learners	Visual aids, chunking durations, peer support, step-by-step guidance	Number lines, clock diagrams, TAs
On-track learners	Standard word problems with mixed addition and subtraction	Worksheets, small group discussion
Advanced learners	Create & solve own problems, explain reasoning in writing/presentations	Extension cards, problem-creation templates

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Extension Activity

• Create Your Own Problem: Pupils design a time calculation word problem involving start and finish times with a set duration. They then exchange problems with a partner and solve each other’s challenges, explaining their reasoning.

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Assessment Opportunities

• Observation of paired and individual work solving time problems.
• Mini-whiteboard quick quizzes for instant feedback.
• Written explanations or verbal sharing during plenary.
• Use of visual aids as evidence of scaffolded understanding.

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Teacher Reflection Prompts

• Were pupils able to transition from mental methods to more formal written strategies?
• Did the use of number lines and clocks support learners who struggled?
• How effectively did advanced learners engage with creating their own problems?
• Were success criteria clear and achievable for all pupils?
• What adjustments can be made for Lesson 3 to consolidate learning or add further challenge?

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This structured yet flexible lesson ensures deep engagement with real-world time problems while reflecting the Curriculum for Wales priorities on numeracy, problem-solving, and communication. It supports diverse learners through thoughtful differentiation and lifts higher-attaining pupils with creative problem design, aiming for confident, measurable mastery of time calculations.