• 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 18, 23, 23, 8 is 18. Find the mean absolute deviation. → 5Prompt: Find how far each value is from the mean (ignore signs).
2. Find the upper quartile (Q3) of: 5, 5, 8, 35, 31, 10, 34 → 34Prompt: Order the data and find the median.
3. Mateo's scores: 17, 20, 23, 20. Mei's scores: 14, 26, 20, 20. Both have mean 20. Whose scores are more consistent (smaller MAD)? (Mateo / Mei) → MateoPrompt: 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 141 cm and Class B's is 161 cm. Both have a mean absolute deviation of 5 cm. The difference in means is how many MADs? → 4Prompt: Find the difference between the means.
2. Minutes of daily reading. Mei's group: 14, 18, 28, 19, 12, 20, 16. Fatima's group: 17, 24, 32, 23, 18, 26, 20. Using medians, which group typically reads for longer? (Mei's group / Fatima's group / They are the same) → Fatima'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 8 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. Two basketball players' points per game: Hiro has median 18 and IQR 9; Mei has median 18 and IQR 7. Who is more consistent? (Hiro / Mei) → MeiPrompt: Consistency is about spread, not the average.
2. Minutes of daily reading. Ethan's group: 16, 23, 16, 20, 14, 15, 30. Arjun's group: 21, 26, 22, 25, 20, 19, 35. Using medians, which group typically reads for longer? (Ethan's group / Arjun's group / They are the same) → Arjun's groupPrompt: Order each list and find the middle value.

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