• 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 15, 19, 17, 12, 22 is 17. Find the mean absolute deviation. → 2.8Prompt: Find how far each value is from the mean (ignore signs).
2. Find the upper quartile (Q3) of: 23, 22, 48, 45, 33, 23, 13 → 45Prompt: Order the data and find the median.
3. Hiro's scores: 13, 14, 15, 14. Ines's scores: 10, 18, 14, 14. Both have mean 14. Whose scores are more consistent (smaller MAD)? (Hiro / Ines) → HiroPrompt: 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 146 cm and Class B's is 150 cm. Both have a mean absolute deviation of 2 cm. The difference in means is how many MADs? → 2Prompt: Find the difference between the means.
2. Minutes of daily reading. Felix's group: 22, 25, 24, 28, 10, 28, 29. Arjun's group: 24, 28, 29, 34, 15, 33, 35. Using medians, which group typically reads for longer? (Felix's group / Arjun's group / They are the same) → Arjun'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. Class A's mean height is 141 cm and Class B's is 153 cm. Both have a mean absolute deviation of 4 cm. The difference in means is how many MADs? → 3Prompt: Find the difference between the means.
2. Two basketball players' points per game: Fatima has median 18 and IQR 12; Ben has median 18 and IQR 15. Who is more consistent? (Fatima / Ben) → FatimaPrompt: Consistency is about spread, not the average.

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