I want numbers to appear in the below mentioned format

56.30 = 56
57.50 = 58
56.49 = 56
57.51 = 58

Using roundup, rounddown & round I can achieve desired functionality? Which is the best way to do this

When I perform addition and substraction on the converted cells it consider decimal places and show deviated result.

How can I get the desired results.

56+58+56+57 = 227 (CORRECT)
56.30+57.50+56.49+57.51=227.80(INCORRECT)