1/10 or 0,1 and 1/4 or 0,25

http://en.wikipedia.org/wiki/Ratio

one tenth is 1/10, and one quarter is 1/4. there are a second set of numbers for counting that goes. 1 First 2 Second 3 Third 4 Fourth 5 Fifth 6 Sixth 7 Seventh 8 Eighth 9 Ninth 10 Tenth and so on if you say the number one before these numbers, for example "one ninth" then it means if the thing is cut into 9 pieces, this is 1 if those pieces, or 1/9. And if you say "two ninths" then it means if the thing is cut into 9 pieces, this is 2 of those pieces, or 2/9 "first" and "second" are only used for the order of things, for example the winner of a race comes first, and the person right after them is second. so we would never say 1/2 as "one second" instead we say "one half" and for 1/4 we either say "one quarter" or "one fourth" both are correct.