"one third" or "one-third" ?

"one third" or "one-third" ? one-third of z one third of one ...another...a third...还是the third by one-third什么意思 one third 中间有-吗 one-thirds与one-third哪个对? what’s one third and one half a third与one third 有什么异同 The third one翻译成中文是什么意思 one and a third billion是什么意思? twenty-third,fifty-one的基数词!