Decimal places in Formula Fields

Decimal places in Formula Fields

I want to multipy a numeric field with two decimal places (Shares) times a currency field (Per_Share) with two decimal places. The result, a formula field (Total) should be of the currency type with two decimal places. When I do this (GUI), I do not get trailing zeroes. For example, if I multiply 2 * $4.55, I get $9.1 but want to get $9.10. I tried scripting, decimalplaces = 2, but the system just ignores that.
Thanks.
Frank Driscoll