Build, check and explain: fraction model partners

roles. Write your prediction, build the model, use Check model and answer, then explain any change in your thinking. Save an SVG of one completed model or draw it on this sheet.

model-1. Set 4 equal intervals per whole. Place a point at 3/4. How many intervals did you travel from zero?

Answer: 3. The five tick marks from 0 through 1 enclose four intervals. Travel three intervals; the point marks the endpoint.

Look for:

• The model matches the whole, partitions and selected amounts in the task.
• The answer includes the correct unit or refers to the requested count.
• The explanation connects the model to the answer.

Teacher response: Counting zero as the first interval.

explain-1. Before building: what do you predict? After checking: sketch the model and explain which part of it supports your answer.

Answer: Accept a prediction followed by a corrected, accurate explanation; a changed prediction is useful evidence of learning.

model-2. Use 12 cm wholes. Show 2/3 on strip A and 4/6 on strip B. How many centimeters are shaded on each?

Answer: 8. Both wholes are 12 cm. Two thirds and four sixths each measure 8 cm; both shaded endpoints agree.

Look for:

• The model matches the whole, partitions and selected amounts in the task.
• The answer includes the correct unit or refers to the requested count.
• The explanation connects the model to the answer.

Teacher response: Adding the same number to numerator and denominator.

explain-2. Before building: what do you predict? After checking: sketch the model and explain which part of it supports your answer.

Answer: Accept a prediction followed by a corrected, accurate explanation; a changed prediction is useful evidence of learning.

model-3. Use a 12 cm whole for A and a 24 cm whole for B. Shade 1/2 of A and 1/4 of B. How many centimeters are shaded on each?

Answer: 6. One half of 12 cm is 6 cm; one quarter of 24 cm is also 6 cm. Different fractions can describe equal lengths when wholes differ.

Look for:

• The model matches the whole, partitions and selected amounts in the task.
• The answer includes the correct unit or refers to the requested count.
• The explanation connects the model to the answer.

Teacher response: Comparing fraction labels as physical amounts without checking the whole.

explain-3. Before building: what do you predict? After checking: sketch the model and explain which part of it supports your answer.

Answer: Accept a prediction followed by a corrected, accurate explanation; a changed prediction is useful evidence of learning.

transfer. A ribbon A is 12 cm long and ribbon B is 24 cm long. One third of A and one sixth of B are coloured. Are the coloured lengths equal? Are the fraction numbers 1/3 and 1/6 equal? Explain both answers.

Answer: Both coloured lengths are 4 cm. The fraction numbers are not equal: 1/3 > 1/6. Equal physical lengths here come from different-sized wholes.

Look for:

• Calculates or models each 4 cm coloured length.
• Separates equality of lengths from inequality of the fraction numbers.
• Names the 12 cm and 24 cm reference wholes.

guide. Suggested timing: 2 minutes to set roles, 5 minutes for each of the three challenges, 3 minutes for the paper transfer.

Teacher response: Ask what the whole is before accepting an answer. A correct app response confirms the configured model and number; read the explanation to assess reasoning. The saved SVG preserves a model, not a student score.