It is neither.
The word is hyphenated, like so: twenty-third.
Twenty five minus one third is 24 and 2/3. You may have also meant twenty five minus one third of twenty five. That would be 16 and 2/3.
One third of twenty thousand dollars is $6666.67 One third of twenty dollars is $6.67
Yes, twenty one are both separate words.
The ordinal number is twenty-third.(The fractional value 1/23 is one twenty-third.)
Three and one hundred twenty five thousandths.
One third of 120000 is 40000
Twenty-three and a third percent.
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Twenty-four
0.04347826086957
40
Twenty six and one third is greater.