Let Principal = P, Rate = R % per annum (p.a.) and Time = n years. Then,
I. When interest is compound Annually:
Amount = P(1+R/100)n
II. When interest is compounded Half-yearly:
Amount = P[1+(R/2)/100]2n
III. When interest is compounded Quarterly:
Amount = P[ 1+(R/4)/100]4n