Math lesson plan · 5th grade (Year 6 in England) · 30 minutes
Use the mean to find a missing value
Statistics and probability
CCSS 6.SP.B.5.CEngland: Y6 Statistics
Objective and success criteria
Students will: Use the mean to find a missing value.
- 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: Find the mean of a small set of data
Leads to: the next skill in this area.
Materials: Squared paper for charts, Class survey data, Sticky notes for a live chart, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 4 min
- Quick retrieval from earlier learning (Find the mean of a small set of data). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Find the mean of 19, 19, 21, 19, 17. → 19Prompt: Add all the numbers.
- Lucia found the mean of 6, 2, 5, 9 by adding them and dividing by 3. Spot the mistake. What is the correct mean? → 5.5Prompt: How many numbers are there?
- Find the mean of 11, 7, 15. → 11Prompt: Add all the numbers.
Hook · 3 min
- Take a quick class survey (favorite fruit, travel to school) and ask what the results tell us.
- Share the objective: Use the mean to find a missing value. Read the success criteria together.
I do: model it · 7 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: The mean of 5 numbers is 12. 4 of the numbers are 9, 10, 5, 20. What is the missing number?
- Step 1: 5 × 12 = 60
- Step 2: 60 − 44 = 16
- Answer: 16
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 6 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- The mean of 3 numbers is 9. 2 of the numbers are 16, 5. What is the missing number? → 6Prompt: The total of all 3 numbers is 3 × 9.
- Mei has a mean score of 11 points after 4 games. How many points does Mei need in the next game to raise the mean to 13? → 21Prompt: Total so far: 4 × 11.
You do: independent practice · 7 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 6 questions are on the student sheet below, with answers in the key.
Exit ticket · 3 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- The mean of 4 numbers is 13. 3 of the numbers are 20, 11, 7. What is the missing number? → 14Prompt: The total of all 4 numbers is 4 × 13.
- Ava has a mean score of 20 points after 4 games. How many points does Ava need in the next game to raise the mean to 22? → 30Prompt: Total so far: 4 × 20.
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: Find the mean of a small set of data.
- 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
- 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-5.
Free lesson plan from eurekami.com/lesson-plan-builder