Have children practice until they perfectly master the task.
Steps
STEP 1
Children separate a larger group of up to 11 objects into two smaller groups.
Repeatedly separate a group of objects into smaller groups per the table below. For example, 2 pencils from 2 pencils leaves 0 pencils, 8 coins from 10 coins leaves 2 coins, and 9 cars from 11 cars leaves 2 cars, etc.
When children are ready, have them separate the object groups themselves.
Children must perfectly master the operations listed in the table before proceeding to the next phase of the lesson.
STEP 2
Children separate groups of objects they can't see, but can imagine (bears, mountains, trees).
Using the table above as a guide, ask children to call out the answer to questions such as, 'How many are one shoe from three shoes?' and 'How many are nine frogs from eleven frogs?'
Give numerous exercises on each number, with constant reviews, until children can recite each operation in the table with great accuracy and rapidity.
STEP 3
In this phase, do not mention objects. Children subtract numbers directly.
Using the table above as a guide, ask children to call out the answer to questions such as, 'How many are one from three?' and 'How many are four from six?'
Give numerous exercises on each number, with constant reviews, until children can perform each operation with great accuracy and rapidity.
STEP 4
Direct children to practice writing and reciting the subtraction problems listed in the table above. For example, they would write and then recite:
2 from 11 leaves 9
11 minus 2 is 9
11 - 2 = 9
Repeat for each combination in the table until the children master the tasks.
STEP 5
Have children copy, solve, and recite the following table:
Assess mastery by reading aloud the word problems below and having the children mentally compute and recite the solutions. If children have difficulties, repeat the prior phases and then reassess.