how is balancing equation done iwant a easy method

The easy way is to write down the number of elements of each type on either side of equation. Convert the equation in a simple elemental form as given below.

eg. C₃H₈ + O₂ ---> CO₂ + H₂O      can be written as C₃H₈ + O ---> CO₂ + H₂O  

start balancing from the molecule with maximum number of atoms. In case this is not working, start balancing the atom which appears least number of times. Atoms of elementary gases are balanced last. Finally convert the equation in molecular form again.

C₃H₈ + O ---> 3CO₂ + H₂O  

C₃H₈ + O ---> 3CO₂ + 4H₂O  

C₃H₈ + 10 O ---> 3CO₂ + 4H₂O  

C₃H₈ + 5O₂ ---> 3CO₂ + 4H₂O