Can a fraction whose numerator is less than its denominator be equal to a fraction whose numerator is greater than its denominator? If not, how can

In the proportion

+6 : -3 :: -10 : +5

is not either extreme greater than either mean? What has become of the old rule, ‘greater is to less as greater is to less’?

— William Frank White, A Scrap-Book of Elementary Mathematics, 1908