Round values with 2 decimal places and add 0 if not decimal are present

Round values with 2 decimal places and add 0 if not decimal are present

Hi, how I can round a value maintaining 2 decimal places? I try with Math.round(val) but doesn't work. Takes these numbers as examples:
25 should be converted to 25.00
25.3666 should be rounded to 25.37
25.55333 should be rounded to 25.55

Any help?