Three-Fifth (3/5) is a slur used to describe Blacks in a derogatory way. Same vain as Point-Six. In reference to the 3/5ths Compromise, where the US Gov't decided that slaves (Blacks) only counted as 3/5ths of a person for population reasons.
The word Three-Fifth (3/5) is a racial slur that has been used historically to degrade and dehumanize blacks. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to blacks. If you are unsure about whether or not it is appropriate to use the word Three-Fifth (3/5), it is best to err on the side of caution and avoid using it in any situation.