Lesson objective: Compare lengths of objects both directly and indirectly. Understand that if ​object A is longer than object B and object B is longer than object C, then object A is longer than object C.
This lesson helps to build fluency with comparing lengths of objects indirectly. Images and clues are used here because they allow students to build the relationships between direct and indirect comparison. 
Students engage in Mathematical Practice 7 (Look for and make use of structure) as they use transitivity, indirect comparison to compare length measurement.

Compare length using indirect comparison by finding objects longer than, shorter than, and equal in length to that of a string.

In this particular lesson, I would begin with a variety of animal cards. We could then discuss what students notice about the animals. We could also sort the animals in order on the picture card, stressing to use the language shortest, longest, equal. From there, I would then continue the application of comparing with the length of string and going through the questions that are presented in the task.

It may be difficult for students to notice the string as a tool to compare lengths and use for measurement. Be sure to surface this through class discussions, hoping the students will bring this understanding to light rather than the teacher telling them.

Module 3 begins by extending students’ kindergarten experiences with direct length comparison to indirect comparison whereby the length of one object is used to compare the lengths of two other objects.  Longer than and shorter than are taken to a new level of precision by introducing the idea of a length unit.  Students then explore the usefulness of measuring with similar units. The module closes with students representing and interpreting data.

Find the rest of the EngageNY Mathematics resources at https://archive.org/details/engageny-mathematics.

In this math lesson, learners read the book "How Big Is a Foot?" by Rolf Myller. Then, learners create non-standard units (using their own footprints) and use the footprints to make "beds." As a result, learners explore the need for a standard unit of measure. This lesson guide includes questions for learners, assessment options, extensions, and reflection questions.

This lesson introduces students to the measurable attribute of length and provides practice in measuring length using non-standard units. The lesson is launched using the story Ladybug on the Move by Richard Fowler. Lesson objectives, teaching ideas, and handouts are included.

This resource First Grade Math Talks and was inspired by learning within The Power of Early Mathematics, 2024, a WISELearn Innovation Grant funded WI Department of Public Instruction learning series. powerofearlymath 

(Nota: Esta es una traducción de un recurso educativo abierto creado por el Departamento de Educación del Estado de Nueva York (NYSED) como parte del proyecto "EngageNY" en 2013. Aunque el recurso real fue traducido por personas, la siguiente descripción se tradujo del inglés original usando Google Translate para ayudar a los usuarios potenciales a decidir si se adapta a sus necesidades y puede contener errores gramaticales o lingüísticos. La descripción original en inglés también se proporciona a continuación.)

El módulo 3 comienza extendiendo las experiencias de jardín de infantes de los estudiantes con una comparación de longitud directa con la comparación indirecta por la cual la longitud de un objeto se usa para comparar las longitudes de otros dos objetos. Más largo que y más corto que se llevan a un nuevo nivel de precisión al introducir la idea de una unidad de longitud. Luego, los estudiantes exploran la utilidad de medir con unidades similares. El módulo se cierra con estudiantes que representan e interpretan datos.

Encuentre el resto de los recursos matemáticos de Engageny en https://archive.org/details/engageny-mathematics.

English Description:
Module 3 begins by extending students’ kindergarten experiences with direct length comparison to indirect comparison whereby the length of one object is used to compare the lengths of two other objects.  Longer than and shorter than are taken to a new level of precision by introducing the idea of a length unit.  Students then explore the usefulness of measuring with similar units. The module closes with students representing and interpreting data.

Find the rest of the EngageNY Mathematics resources at https://archive.org/details/engageny-mathematics.