• Quick retrieval from earlier learning (Mean absolute deviation (MAD); Find quartiles and the interquartile range). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. The mean of 10, 14, 10, 12, 4 is 10. Find the mean absolute deviation. → 2.4Prompt: Find how far each value is from the mean (ignore signs).
2. Find the lower quartile (Q1) of: 33, 21, 21, 35, 25, 2, 5, 44, 7, 28, 33 → 7Prompt: Order the data and find the median.
3. Hana's scores: 24, 26, 28, 26. Ines's scores: 22, 30, 26, 26. Both have mean 26. Whose scores are more consistent (smaller MAD)? (Hana / Ines) → HanaPrompt: MAD measures how spread out the data is around the mean.

• Take a quick class survey (favorite fruit, travel to school) and ask what the results tell us.
• Share the objective: Compare two groups using centre and spread. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: Class A's mean height is 145 cm and Class B's is 157 cm. Both have a mean absolute deviation of 3 cm. The difference in means is how many MADs?
• Step 1: 157 − 145 = 12
• Step 2: 12 ÷ 3 = 4
• Answer: 4
• Pause after each step and ask a student to say what comes next.

• Do these together. Students try each step on whiteboards before you reveal it.
• Use the hints as prompts rather than giving the answer.

1. Class A's mean height is 153 cm and Class B's is 169 cm. Both have a mean absolute deviation of 4 cm. The difference in means is how many MADs? → 4Prompt: Find the difference between the means.
2. Minutes of daily reading. Leo's group: 25, 29, 18, 25, 24, 23, 13. Nia's group: 28, 32, 21, 28, 29, 28, 19. Using medians, which group typically reads for longer? (Leo's group / Nia's group / They are the same) → Nia's groupPrompt: Order each list and find the middle value.

• 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.

• Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.

1. Minutes of daily reading. Ines's group: 17, 17, 10, 27, 19, 21, 26. Aisha's group: 24, 25, 16, 36, 28, 27, 31. Using medians, which group typically reads for longer? (Ines's group / Aisha's group / They are the same) → Aisha's groupPrompt: Order each list and find the middle value.
2. Two basketball players' points per game: Ethan has median 18 and IQR 10; Daniel has median 18 and IQR 12. Who is more consistent? (Ethan / Daniel) → EthanPrompt: Consistency is about spread, not the average.

Free online practice with hints and printable worksheets for this skill: eurekami.com/math/grade-7.