STRIP BOARD (including doubles)
f. The Combinations of One Number with Zero as an Addend
Materials: addition strip board and strips
Control Chart 1 and /or Chart II (45 combinations)
Let’s find all of the combinations that make 9. 0+9=___? Our first addend is zero, so we place nothing on the board. Our second addend is 9, so we place the pink strip for 9 on the board. Our sum is 9. This continues until 9+0 is the last combination.
We notice that the first strip is all pink and the last strip is all blue.
Zero doesn’t change the number in addition.
As before the child eliminates the unnecessary combinations.
Control of error: Control Chart 1 and/or Chart II