Math lesson plan · 5th grade (Year 6 in England) · 45 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 · 5 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 28, 29, 29, 30, 28, 30. → 29Prompt: Add all the numbers.
- Elena found the mean of 5, 8, 7, 2 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 27, 24, 21, 28, 20. → 24Prompt: Add all the numbers.
Hook · 5 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 · 10 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 · 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.
- The mean of 5 numbers is 9. 4 of the numbers are 4, 6, 16, 9. What is the missing number? → 10Prompt: The total of all 5 numbers is 5 × 9.
- Kai has a mean score of 10 points after 4 games. How many points does Kai need in the next game to raise the mean to 11? → 15Prompt: Total so far: 4 × 10.
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.
- Noah has a mean score of 10 points after 4 games. How many points does Noah need in the next game to raise the mean to 12? → 20Prompt: Total so far: 4 × 10.
- The mean of 4 numbers is 11. 3 of the numbers are 5, 10, 20. What is the missing number? → 9Prompt: The total of all 4 numbers is 4 × 11.
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