Page 285 - ICSE Math 8

Types of Sets

Finite set: countable elements Overlapping sets

Infinite set: uncountable elements Power set: subsets of a given set

Singleton or unit set Universal set: largest set with all
the given set as its subsets
Empty or null set
Equivalent sets: same number of elements
Disjoint sets
Equal sets: sets with the same elements

Union of sets
A ∪ B means elements of either set A or set B.

Intersection of sets
A ∩ B means common elements of sets A and B.
Operations on Sets
Difference of Two sets
A – B means elements that belongs to A but not to B.

Complement of a set
Set of elements of U that are not in A, a subset of U.

RATIO AND PROPORTION

Ratio
Symbol of Ratio
A : B A ratio is used to express
how many times one
quantity is of the other.
Antecedent Consequent

Comparison of Ratios Dividing a Quantity, A, in
the given Ratio

By converting By making the By cross multiplying
into decimals consequents the antecedents with In ratio x : y In ratio x : y : z
equal the consequents  x   x 
st
1 part:   × A 1 part:  st  × A
 x + y   x + y + z 
nd  y  nd  y 
2 part:   × A 2 part:   × A
 x + y   x + y + z 
 z 
3 part:  rd  × A
 x + y + z 

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