Rebuild Groups and Equal Shares

Model the Unknown Group Role

Start with equal groups

Use the lesson’s 12 counters: draw 3 equal outlines, put one counter in each in turn until all 12 are used. Each group has 4. Now draw groups of 4 until all 12 are used: there are 3 groups. Name which role was unknown each time.

Make a comparison with copies

Return to the 4 cm and 12 cm strips. Draw three 4 cm copies to make 12 cm. Mark one original 4 cm copy and the 8 cm extra length. Count copies for “times as long”; measure the difference for “longer by”.

Try another example: 15 counters go into 3 equal groups. Find the group size and label the roles. A 3 cm strip and a 15 cm strip are compared: find both comparisons and explain.

Rebuild Groups and Equal Shares

Model an Equal Fractional Share

Return to 3 m shared among 4 projects. Draw three 1 m bars. Split each bar into 4 equal parts. One project gets one part from each bar: 3/4 m. Show the other projects’ shares and check that every part is used once.

Try a new amount

A 2 L amount is shared equally into 5 portions. Draw a model, label one whole liter, and find the volume in each portion. Explain how all 5 portions use the 2 L.