Exchange rate-Use Treas. Dept or Fed. Reserve rate? Invert?

[marge]

Hi,

I've always used the Federal Reserve average conversion rate for the year, for some calculations, and the Fed. Res. rate at the end of the year, or the historical rate for the particular date, as applicable. But instructions for the new form 8938 tell us to use the Treasury Dept. rate ("in most cases"). Could someone please tell me, should I be using the Treasury Dept. rate for the rest of the return as well, i.e. Schedule B, form 8891, 2555EZ etc.?

The average Fed.Res. rate for Canada for the 2011 year is 0.9887; the Treas. Dept. reporting rate at Dec. 31/2011 is 1.0180; the Fed. Res. rate at Dec. 30/12 is 1.0168 (no am’t given for Dec. 31st).

Also, to convert CAD to USD, could you please confirm that I should invert the numbers (i.e. multiply 1/1.0180, or 0.9823, times the CAD am’t) to obtain the am’t in USD, so that $10,000 CAD = 9,823?

These are probably simple questions, but I've been searching quite a while for the answers! Thanks very much for any help you can give.