Small Penny Cube

CCSS: 5.MD.5, 5.NBT.7

Georgia’s K-12 Mathematics Standards: 5.NR.1, 5.GSR.8, 6.NR.2

Act 1

Ask students:

  • What do you notice?  Record student responses.
  • What do you wonder?  Record student curiosities and wonders.

Focus question(s): How many pennies will fit in the small cube? How much money is that?

Ask students to:

  • Write down an estimate that is too high.
  • Write down an estimate that is too low.
  • Write down a best guess estimate.
  • Mark each estimate on an empty number line.

Act 2

Ask students what information/tools they need to answer their question.  Give them their information as they ask for it.

NOTE:  From experience (mine and others who have shared with me), students rarely ask for the size of coins.  They do, however, ask for pennies and a ruler along with the dimensions of the cube.  

When they ask, I give groups/pairs of students a small dixie cup of pennies (about 20 or so) and a ruler.  

If students do ask for the dimensions of a penny, they can still be found below.

Coin Specifications

Act 3

Share your solution and strategies.  Compare your strategies and results.

Watch the Act 3 Reveal, then discuss using the questions that follow.

  • How reasonable were your estimates?
  • What might you do differently next time?
  • What did you do well during this task?

Sequels

Small Penny Cube: The Weight of it All!

How much does this Small Penny Cube Weigh?

For Act 2, students may wish to use the pennies and a small scale, or they can use the coin specifications list from Act 2, above.

The Reveal:

The weight of the Small Penny Cube in pounds.

The weight of the Small Penny Cube in grams.

Small Penny Cube 2:  Invasion of the Quarters!

Quarters would fit nicely in this cube as well.  Which would you rather have, a cube of pennies or a cube of quarters?

Small Penny Cube 3: Return of the Pennies!

If this cube was one cubic foot, how much money would it hold?

How much do you think it might weigh?