How can I format an expression in BI Publisher

Hello,

Let's say, for example, I'm using the following expression in one of my RTF templates in BI Publisher: '<?xdofx:4.76*3.29?>'. The result would display on my report as '15.6604'. How can I format the result to display only '15.66'?

The actual expression I'm using in my template is '<?xdofx:C_DISCOUNT_AMT_SUM*C_NET_AMT_SUM?>'. 

Any help will be greatly appreciated.

Thanks!