A = P(1 + r/q)nq
The nq outside the brackets above does not mean "multiplied by nq" but "to the power of nq".
P is the principal (the money you start with, your first deposit)
r is the annual rate of interest as a decimal (5% means r = 0.05)
n is the number of years you leave it on deposit.
q is the number of times per year that the interest is to be calculated.
Sweet's modern business arithmetic: A treatise on modern and practical methods of arithmetical calculations for the use of business and commercial colleges, ... in other educational institutions
