Lesson COG 53
Task: Do basic division.
Prerequisites: COG 23, COG 35, COG 41, COG 43, COG 52, S&L 7
Concept: This activity is basically the inverse of the process involved in multiplication, which is why COG 52 is considered a prerequisite. Again, although the use of rote memorization is ultimately needed, some efforts to demonstrate this concept appear useful. In addition to the concept below, playing cards can be useful in a group setting where this concept is being taught.
Behavioral Objective: When presented with a division problem including a double-digit number (up to 81) divided by a single-digit number (1-9) that will result in a whole number, the student will respond with the correct answer to a 90% accuracy level for 20 trials.
Materials: Make flash cards for each of the possible division problems for single-digit numbers 1 through 9 divided by a double digit where the answer is a whole number (problem on front and answer on back). Make "foot"-shaped designs from poster board that have the numbers 1 through 81 on them. Also needed will be paper, color stickers, and markers.
Task Analysis:
1. Lay the foot shapes in reverse order on the floor with a spacing so that the student can step from one number to the next. Have the student begin at the number 10 and assist him or her in walking toward the number 1, counting each step. Explain how this is the division of 10 divided by 1. Repeat this process for other examples.
2. Place some form of marker, such as a red piece of cloth, on one leg of the student. Start at the number 10, walk toward the number 1, and have the student draw a mark on a piece of paper each time the marked leg is used. Explain that this process is called dividing by twos. On a piece of paper, draw the number 2,0 division symbol, and the number 10. Have the student count the marks he or she made on the paper and tell you what that number is. Show the resulting complete division problem. Continue this process for other even two-digit numbers.
3. Modify Step 2, using color stickers by every third footprint, and demonstrate the "threes" concept.
4. Continue Step 3 for the numbers 4 through 9.
5. Using the flash cards, begin with the ones, then twos, and so forth. Keep repeating the process, focusing on just one number series at a time.
6. Begin introducing the flash cards in a random manner. Continue until the objective is met.