Trigonometry

It is the study of angles and sides and relationship between them in a triangle.

LCM and HCF

LCM : Least Common Multiple 

The LCM of two or more numbers is the least number to be exactly divisible by each of them.

For example : LCM of 2,3,4 and 5 is 60.

Ratio and Proportion

Ratio :

a/b or a : b

a → antecedent

b → consequent

Number System

Sum of Numbers:

• Sum of first n natural numbers                         = n(n+1)/2
• Sum of square of first n natural numbers       = n(n+1)(2n+1)/6