This is why 'whether' is said with reference to both, not to one of the two (e.g. 'whether it is greater or equal' or 'whether it is equal or less'); there are always three cases.
Horregatik galdetzen da biekiko erlazioan ez bakar batekiko erlazioan (ez da galdetzen, adibidez, "handiagoa ala berdina?", edo "berdina ala txikiagoa?", baizik eta hirurak aipatuz, beti).