Help figuring out a checksum algorithm

Hi all, I'm new to the board and I need help.

I am trying to figure out a checksum algorithm. from what I know it is a fairly simple alg but i still am having trouble.

Here is a sample of the data and the checksum:

F0 20 20 31 30 37 2E 37 20 46 4D 32 2E 34 20 20 20 and the Checksum is 3E

Another set of Data is

F0 43 44 20 30 31 20 20 1C 54 52 20 31 31 20 1C 1C and the Checksum is 3A

another is

F0 20 20 31 30 37 2E 37 20 46 4D 32 2E 35 20 20 20 and the checksum is 3D

Any help would be greatly appreciated.