"skybird23" wrote:
I have a formula which i do not understand?
PMT(D412,E4,-C4) I know is payment but what
does it mean, what will do this formula what is
it looking for????

The first thing you should do is use Help to learn
about the PMT function. You will find that its
parameters a PMT(rate,nper,pv,fv,type).

In the example you give, PMT() computes the
periodic payment necessary to reduce an initial
principle amount given in C4 (a loan, for example)
to zero over a number of periods given in E4 at a
periodic interest rate given in D412(!).