You will need 2 empty boxes and centimetre cubes.

Choose one box. Estimate how many centimetre cubes the box can hold.
Fill the bottom of the box with one layer of cubes. How many cubes are in that layer? How many layers can fit in the box? How do you know?
How many cubes can the box hold altogether? Describe how you found your answer. Record your answer on the box.
Without filling it completely, find how many cubes the second box can hold. Describe the strategy you used. Use cubes to check your answer.

How can you find the volume of a box without filling it completely? Will your answer be exact? Explain. How can you find the volume of a box without using cubes?

Don't know what boxes you use. However, you can use the cubes to measure each dimension (height, width and length) and calculate from there. For the last question, do you have a tape measure?