• 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 22, 15, 23, 24, 16 is 20. Find the mean absolute deviation. → 3.6Prompt: Find how far each value is from the mean (ignore signs).
2. Find the upper quartile (Q3) of: 44, 43, 17, 49, 20, 34, 42 → 44Prompt: Order the data and find the median.
3. Arjun's scores: 20, 21, 22, 21. Priya's scores: 18, 24, 21, 21. Both have mean 21. Whose scores are more consistent (smaller MAD)? (Arjun / Priya) → ArjunPrompt: 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 151 cm and Class B's is 166 cm. Both have a mean absolute deviation of 5 cm. The difference in means is how many MADs? → 3Prompt: Find the difference between the means.
2. Minutes of daily reading. Ana's group: 15, 27, 11, 28, 16, 28, 25. Luis's group: 24, 33, 20, 35, 24, 34, 31. Using medians, which group typically reads for longer? (Ana's group / Luis's group / They are the same) → Luis'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. Sam's group: 27, 19, 10, 23, 27, 13, 13. Fatima's group: 31, 27, 14, 28, 31, 20, 20. Using medians, which group typically reads for longer? (Sam's group / Fatima's group / They are the same) → Fatima's groupPrompt: Order each list and find the middle value.
2. Two basketball players' points per game: Fatima has median 18 and IQR 9; Mateo has median 18 and IQR 6. Who is more consistent? (Fatima / Mateo) → MateoPrompt: Consistency is about spread, not the average.

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