Measuring Blocks
Materials
 Unifix cubes
 Large blocks in different sizes or varying lengths of sentence strips
Note: The large blocks or the cutup lengths of sentence srtips need to measure a whole number of unifix cubes whose combined length is less than or equal to 20 unifix cubes.
Actions
 Have students work in pairs. Give each pair two blocks or strips to measure using unifix cubes. After they have measured their block, say,
Ask your partner how many unifix cubes long their block/paper strip is. How long will the two different blocks be together if they are laid endtoend? First try to figure this out. Then put the blocks endtoend and measure it to check your answer.

Ask students to explain how they solved the problem and whether their answer checked out correctly. Even if students added correctly, they may not have lined up the unifix cubes very carefully and could get different lengths. This is a good opportunity to talk about how important it is to be careful when measuring. The teacher may also need to ensure that all students are "clicking" their unifix cubes together so that there aren't gaps between the unifix cubes which would alter the measurements.

Finally, ask the students to write equations to represent their work.
For students who are ready for a more complex question ask,
Imagine you put another block endtoend with the first one you measured. Together, they measure [X number] of unifix cubes. How long is the new block? Draw a picture to explain how you know.