Using money to clarify the decomposition subtraction algorithm

Abstract

2. Borrowing readiness with partial use of algorithm. The child is presented number combinations in subtraction form and is merely to decide if the procedure can take place. This serves to aid in erasing the child's established pattern of merely finding the difference between the larger and smaller digit of the same place value. 3. Working with money. Since dimes and pennies lend themselves so well to place value, they become an effective means of communication of the idea of regrouping. 4. Use of the algorithm. The retrained student can now proceed, using the preparatory materials as the basis for making a more mature and appropriate arithmetic attack on subtraction problems.