Were Black People Really Look At As Being 3/5 Of A Person During Slavery?

Eye would have to start off by saying yes.Eye had always heard a statement  by some of our leaders that the U.S Constitution says that black people are 3/5 of a human being. And they say that this is why the whites during slavery treated our ancestors like cattle and beast of the field. But when eye  went and looked it up eye couldn't find it anywhere.But eye did find something else on it it that was interesting and we will share it with you. PEACE