Order six and three tenths repeating, negative six and four ninths, 630%, and 6.1 from least to greatest. six and three tenths repeating, 630%, negative six and four ninths, 6.1 six and three tenths repeating, 630%, 6.1, negative six and four ninths 6.1, negative six and four ninths, six and three tenths repeating, 630% negative six and four ninths, 6.1, 630%