1. Let Principal = P, Rate = R% per annum, Time = n years.

  2 . When interest is compound Annually:

       Amount = P \( [ 1 + \frac {R } { 100}]^n\)

  3. When interest is compounded Half-yearly:

       Amount = P \( [ 1 + \frac {(R/2) } { 100}]^2n\)

  4 .When interest is compounded Quarterly:

      Amount = P \( [ 1 + \frac {(R/4) } { 100}]^4n\)

 5. When interest is compounded Annually but time is in fraction, say 3 \( \frac { 2 } { 5 } \) years.

      Amount = P \( [ 1 + \frac {R } { 100}]^3\) X \( [ 1 + \frac { ​​2/5 ​​​​ R} { 100}]\)

6. When Rates are different for different years, say R₁%, R₂%, R₃% for 1^st, 2^nd and 3^rd year             respectively

   Then, Amount = P \( [ 1 + \frac {R1 } { 100}]\)\( [ 1 + \frac {R2 } { 100}]\)\( [ 1 + \frac {R3 } { 100}]\)

7. Present worth of Rs. x due n years hence is given by:

    Present Worth =\( \frac {X } { [1 + R/100] } ) ^n \)