How to Round off the total amount billed?

Hi Team,

I got a requirement where i need to round of the total amount billed, as shown below:

if the amount billed  = 700.5, it should be rounded to 701.00

that is if the decimal points are greater than or equal to .5, then we need to round it of to next whole number, 700.5 should become 701.00

if it is less than .5, that is 700.4 ,then we need to make  it as 700.00.

Could any one please suggest any system function or logic to accomplish this.

Thanks & Regards,

Terry