It has gone pretty well. I have most of them working just fine.
I have been thrown by this one though:
var calc = tax_per_year*(Math.pow((inflation - 0.015), (career_start-age)))*((1 - Math.pow(inflation, (%(career_start - age)))/(1 - inflation)));
Or have a look at the W3C Reference. Math.abs (W3C Reference)