Step One: Gather materials.
- 1 pound of clear glass gems
- Permanent marker
Step Two: Draw triangles with the marker on the paper.
Step Three: Write two numbers in two corners of the triangles.
Step Four (optional): The child can use the gems as counting manipulatives or add the two numbers up by counting the glass gems.
To learn how to compose a number:
Step Five: The child writes the total in the empty corner of the triangle. This adding numbers together, or building a number is called composing a number. Another way to say composing numbers is to think about putting numbers together.
Then, to learn the concept of decomposing numbers:
Step Six: Draw another triangle and start with a higher number and a lower number. The child can use the clear glass gems to subtract by counting out the manipulatives. This taking apart of a number is called decomposing a number. Another way to say decomposing numbers is to say "taking apart" a number.
Then, write out the addition and subtraction sentences using boxes with the composed and decomposed numbers.