what is an equation for this?

Noah deposits $20 in a savings account at the beginning of January and makes no more deposits. The bank adds interest to his account at a rate of 1.2% per month.

m=month
a=amount

A=P\left(1+\frac{r}{n}\right)^{nt}

P=principal, r=rate of interest, n=number of compoundings in one year. In this case, 12.
t=time invested.

A=20\left(1+\frac{.012}{12}\right)^{12}

Is the amount in the bank after one year.