• 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 16, 13, 14, 22, 25 is 18. Find the mean absolute deviation. → 4.4Prompt: Find how far each value is from the mean (ignore signs).
2. Find the upper quartile (Q3) of: 40, 44, 14, 23, 38, 24, 44, 4, 47, 40, 6 → 44Prompt: Order the data and find the median.
3. Liam's scores: 10, 13, 16, 13. Mateo's scores: 8, 18, 13, 13. Both have mean 13. Whose scores are more consistent (smaller MAD)? (Liam / Mateo) → LiamPrompt: 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 155 cm and Class B's is 161 cm. Both have a mean absolute deviation of 2 cm. The difference in means is how many MADs? → 3Prompt: Find the difference between the means.
2. Minutes of daily reading. Lucia's group: 30, 27, 19, 29, 21, 12, 28. Zoe's group: 39, 39, 28, 39, 32, 20, 37. Using medians, which group typically reads for longer? (Lucia's group / Zoe's group / They are the same) → Zoe'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 156 cm and Class B's is 162 cm. Both have a mean absolute deviation of 2 cm. The difference in means is how many MADs? → 3Prompt: Find the difference between the means.
2. Minutes of daily reading. Kwame's group: 22, 13, 11, 18, 14, 14, 21. Kofi's group: 27, 20, 18, 26, 22, 19, 27. Using medians, which group typically reads for longer? (Kwame's group / Kofi's group / They are the same) → Kofi'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.