Help required in Maths

[Muhammad Ali Shah]

Let p1 is the price of commodity in year 1

Let q1 is the quantity of commodity in year 1

Let v1 is the value of commodity in year 1

then p1*q1=v1

similarly for 2nd year let p2*q2=v2

now growth in p in percentage = (p2-p1)/p1*100

growth in q in percentage = (q2-q1)/q1*100

growth in value in percentage = (v2-v1)/v1*100

(p2-p1)/p1*100+(q2-q1)/q1*100 is not equal to (v2-v1)/v1*100

i.e. growth in p +growth in q is not equal to growth in v.

Now I want to know how much the growth is attributed by price and quantity.Is there any formula or technique?

Thanks and Regards