The purpose of this activity is for students to measure length by physically lining up length units that do not connect. Students discuss how measuring with paper clips is the same and different as measuring with connecting cube towers.

If both partners agree on a measurement other than 9 paper clips, have them compare their thinking with another group and consider asking:

• “¿Por qué crees que tu número de clips es diferente?” // “Why do you think your number of paper clips is different?”
• “¿En qué es diferente la forma en que usaste los clips para medir?” // “What is different about the way you used the paper clips to measure?”

• Invite previously identified students to share.
• “¿En qué se parece medir con clips a medir con cubos encajables? ¿En qué es diferente?” // “How is measuring with paper clips the same and different as measuring with connecting cubes?” (Paper clips don’t connect. You need to be careful about laying paper clips down, they move easily. You still start at one endpoint of the object you measure and end at the other endpoint.)

The purpose of this activity is for students to analyze representations of length measurements. Students determine that two of the measurements are inaccurate because there are gaps between length units or some length units overlap. Students identify that in order to measure accurately, they need to lay the length units in a straight line, directly next to each other, touching, but not overlapping (MP6).

• “¿Qué consejos les darían a Andre y a Clare la próxima vez que ellos midan?” // “What advice would you give Andre and Clare the next time they measure?” (Place each paper clip end to end. Make sure they do not overlap and that there are no gaps between them.)

The purpose of this activity is for students to measure the length of tape strips using paper clips as the length unit. Students apply what they have learned in the previous two activities to measure accurately.

Set up tape strips of the designated lengths around the classroom, labeled with letters (A‒F). Assign each group a tape strip to start with and then have them rotate to a new strip, as time allows.

• Invite previously identified students to share.
• “¿Cómo saben que midieron la cinta C correctamente?” // “How do you know that you measured Tape C correctly?” (The paper clips had no gaps and no overlaps, the paper clips started at the beginning of the tape and went to the end of the tape.)

• “Los dos grupos se aseguraron de que no hubiera espacios ni sobreposiciones en sus clips. Los dos grupos dijeron que la cinta C mide 12 clips de largo” // “Both groups made sure there were no gaps or overlaps with their paper clips. Both groups said Tape C is 12 paper clips long.”