Math lesson plan · 6th grade (Year 7 in England) · 45 minutes
Calculate the mean, including decimal answers
Statistics and probability
CCSS 6.SP.B.5.CEngland: KS3 StatisticsEngland: GCSE Foundation Statistics
Objective and success criteria
Students will: Calculate the mean, including decimal answers.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Mean, median, mode and range
Leads to: Mean absolute deviation (MAD); Choose the best average and see how outliers affect it
Materials: Squared paper for charts, Class survey data, Sticky notes for a live chart, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Mean, median, mode and range). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Find the mean of: 15, 20, 17, 21, 22 → 19Prompt: Add all the numbers.
- Find the median of: 8, 15, 8, 4, 3, 27, 25, 4 → 8Prompt: Put the numbers in order first.
- Find the range of: 13, 5, 13, 13, 15, 3 → 12Prompt: Range = largest − smallest.
Hook · 5 min
- Take a quick class survey (favorite fruit, travel to school) and ask what the results tell us.
- Share the objective: Calculate the mean, including decimal answers. Read the success criteria together.
I do: model it · 10 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Data (kg of recycling collected each week): 11, 25, 60, 26, 34. Find the mean.
- Step 1: 11 + 25 + 60 + 26 + 34 = 156
- Step 2: 156 ÷ 5 = 31.2
- Answer: 31.2
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 10 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Data (daily high temperatures (°C)): 17, 27, 20, 21, 13. Find the mean. → 19.6Prompt: Add all the values.
- Four runners' 100 m times in seconds: 11.6, 11.3, 12.5, 14.9. Find the mean time. → 12.575Prompt: Add the four times carefully, lining up decimal points.
You do: independent practice · 10 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 5 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Four runners' 100 m times in seconds: 13.6, 16.6, 11.1, 16.6. Find the mean time. → 14.475Prompt: Add the four times carefully, lining up decimal points.
- Tariq wants a mean score of 20 over 6 games. The first 5 scores are 15, 20, 14, 26, 25. What must Tariq score in the last game? → 20Prompt: A mean of 20 over 6 games needs a total of 20 × 6.
Watch out for
- Forgetting to put data in order before finding the median.
- Reading a bar's height wrongly when the scale goes up in 2s or 5s.
Support and stretch
Support
- Review first: Mean, median, mode and range.
- Use concrete materials: squared paper for charts.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Move on to: Mean absolute deviation (MAD); Choose the best average and see how outliers affect it.
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/math/grade-6.
Free lesson plan from eurekami.com/lesson-plan-builder