- Twin primes
Twin primes are pairs of prime numbers which differ by 2. For example, 3 and 5,
5 and 7, 11 and 13, etc, are all twin primes. The idea may be taught orally supported
by relevant text material in Braille.
- Prime factor
A factor that cannot be expressed as a product of 2 numbers aside from one and
itself is called a prime factor. In otherwords, a number that cannot be factorized
further is called a prime factor.
- Composite number
Numbers which are not primes are said to be composite numbers. In other words,
a number which has more than two divisors is called a composite number. The
procedure followed in the identification of a prime number can be followed for
identification of a composite number also.
To enable the child to understand the concept, provide him/her with some beads, say
for instance 8 beads. Now, ask the child to regroup the beads other than the groupings
of 1‘s and 8‘s. If such a grouping could be done then 8 is a composite number.
In this case, the beads can be grouped in 2’s, 4’s and hence a grouping other than the
groupings of 1’s and 8’s is possible and therefore 8 is a composite number.
- Cardinal Number
The number of elements (objects) present in a set (or group) is the cardinal
number of the set (or group).
Few beads might be given to the child and he/she be asked to count them. The
number of beads may be increased or decreased and be given to different children, so
that the children are able to say different numbers.
