Page 55 - Math Skill - 5

Factors and Multiples 53

MIND MAP

Factors and Multiples

Numbers

EVEN ODD PRIME CO-PRIME COMPOSITE
Divisible Not Divisible having exactly having only ‘1’ as having more
by 2 by 2 two factors 1 their common factor than two factors
and itself i.e. (3, 7)

Divisibility Test TWIN PRIME
DIVISOR RULES Pair of prime members
2 If unit place digits are 0, 2, 4, 6, 8 differ by 2
3 Sum of digits is divisible by 3 i.e. (3, 5) (5, 7)

4 Last two digits of number is divisible by 4
5 If ones place is either 0 or 5
6 If number is divisible by 2 and 3 both
8 Last three digits of number is divisible by 8
9 Sum of digits is divisible by 9
10 If unit place of number is 0 For any two numbers a and b
11 Difference of sum of digits at even places HCF × LCM = a × b
and odd places is either 0 or multiple of 11

Factors

� A factor is always smaller than or Multiples
equal to its number. � A multiple is always greater than or
� A factor of a number is an exactly equal to its number.
divisor of that number. � Every number is a multiple of itself.

� 1 is the factor of every number. � Multiples of any number can be infinite.