Lining up the decimals and subtracting just like you do with whole numbers is the best way to approach the subtraction of decimal values.
2.55 2.83 - 2.43 - .92 -------- --------- .12 1.91 2.47 3.69 - 1.44 - 2.57 -------- --------- 1.03 1.12
Now you get to try a few for yourself.