Looks great, thanks for sharing Roger.

Hi Roger, here is set of additional functions that you can add to your project. These are functions used in excel to calculate interest rates and annuities

function vpm(k : number,n : number,t : number) do
if n = 0 then
0
else
if t = 0 then
k / n
else
let Pv := t;
let APR := number(k);
let R := APR / 100 / 12;
let numerator := Pv * R;
let x := 1 + R;
for i in range(1, n) do
x := x * (1 + R)
end;
let denominator := 1 - 1 / x;
numerator / denominator
end
end
end;
function fv(Pv : number,R : number,n : number) do
let y := 1 + R;
let x := y;
for i in range(1, n) do
x := x * y
end;
Pv * x
end;
function princPer1(k : number,n : number,t : number) do
if n = 0 then
k
else
if t = 0 then
vpm(k, n, t)
else
(k * t) / (pow(1 + t, n) - 1)
end
end
end;
function amortissementPn(k : number,n : number,t : number,p : number) do
let A := princPer1(k, n, t);
if p = 1 or t = 0 then
A
else
pow(1 + t, p - 1) * A
end
end;
function intPer(k : number,n : number,t : number,p : number) do
let m := vpm(k, n, t);
let apn := amortissementPn(k, n, t, p);
m - apn
end