| The following example is taken from Bruner
(1973, as cited in Kearsley 1994b): The concept of prime numbers appears to be more readily grasped when the child, through
construction, discovers that certain handfuls of beans cannot be laid out in completed
rows and columns. Such quantities have either to be laid out in a single file or in an
incomplete row-column design in which there is always one extra or one too few to fill the
pattern. These patterns, the child learns, happen to be called prime. It is easy for the
child to go from this step to the recognition that a multiple table, so called, is a
record sheet of quantities in completed multiple rows and columns. Here is factoring,
multiplication and primes in a construction that can be visualized.
Instructional Objective: Recognize and define a prime number.
Methodology:
Ask the student to get a handful of pennies, beans, or any
other countable object.
Show the students 6 pennies. Show that six pennies
can be organized into two groups of three, three groups of two, or one group of six.
Ask the student to count out 8 pennies and organize
the pennies into as many EQUAL groups as they can. .
Show answer.
Ask the student to count out 18 pennies and organize
the pennies into as many EQUAL groups as they can.
Show answer.
Ask the student to count out 7 pennies and organize
the pennies into as many EQUAL groups as they can.
Show answer.
Ask the student to count out 13 pennies and organize
the pennies into as many EQUAL groups as they can.
Show answer.
State that 7 and 13 are prime numbers, while 6, 8 and 18 are
not. Ask the following questions: What is a prime number? What is the rule or principle
for determining whether a number is prime or not?
Explain the principle that when a certain number of pennies
can only be grouped into one equal row or column, then that number is called a prime
number.
Show a selection of numbers or examples of different groups
of coins. Ask the student to identify which ones are prime.
Show answer.
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