公平・こうへい: Fair.

同等・どうとう: equal (but no moral judgement to it) 'This engine does the work of 4 horses' 'I have the strength of a dozen oxen!'

等量・とうりょう: equal amount - usually used in math or science

 平等 びょうどう: even-steven. (to cut the cake into equal pieces, to treat your adopted kids and your biological kids equally)