ADDITION CHARTS AND COMBINATION CARD EXERCISES
c. Passage from Chart III to Chart IV (the Half Chart)
…box of combination cards
…Control Chart I and IV (which has only sums)
In the same way as the child passed from Chart I to Chart II, a group activity may be conducted to show that some of these sums on Chart III can be eliminated. The combinations are reconstructed, going along the diagonal. This 4 was made by 1+3, this by 2+2, and this by 3+1, so we can eliminate it. When the elimination is complete, we have Chart IV.
The child fishes for a combination, reads it and writes it down on his paper, i.e. 5+9. On the pink column at the left, he places his finger on the first addend and goes all the way to the end of that row. Then he places his other finger on the second addend (in the same pink column) As before the two fingers are moved toward each other, and at the meeting place in the sum. When the child pulls out a combination, which has the first addend greater than the second, he will find that he can’t do it. We simply reverse the order of the addends.
Control of error: Control Chart I