一も二も無く[ichimonimonaku] unhesitatingly
一言二言[hitokotofutakoto] a word or two
一石二鳥[issekinichou] killing two birds with one stone
一二に及ばず[ichininioyobazu] right away
一姫二太郎[ichihimenitarou] It's good to have a girl first and then a boy

うり二つ[urifutatsu] as alike as two melons (two peas in a pod)
黄道十二宮[koudoujuunikyuu] twelve signs of the zodiac
二度[futatabi] again
最小二乗法[saishounijouhou] least-squares method
三十二分音符[sanjuunibuonpu] 32nd note

黄道十二宮[koudoujuunikyuu] twelve signs of the zodiac
丸十[marujuu] cross in a circle
五十音[gojuuon] the Japanese syllabary
五十音順[gojuuonjun] the syllabary order
五十三次[gojuusantsugi] the 53 Toukaidou stages

五十年祭[gojuunensai] jubilee
五十歩百歩[gojuppohyappo] six of one and a half dozen of the other
五十路[isoji] age fifty
三十戸[sanjikko] thirty houses
三十三所[sanjuusansho] any of a number of sets of thirty-three holy places enshrining Avalokitesvara (esp. those comprising a popular pilgrimage in the Kinki region)

御誕生日おめでとうございます[otanjoubiomedetougozaimasu] Happy Birthday
また明日[mataashita] see you tomorrow
旭日[kyokujitsu] rising sun
旭日昇天[kyokujitsushouten] full of vigor and vitality (like the rising sun) (vigour)
或日[aruhi] one day (e.g. "one day while studying, ..")

一日の長[ichijitsunochou] superiority
一日一日[ichinichiichinichi] gradually
一日一夜[ichinichiichiya] all day and night
一日増しに[ichinichimashini] day by day
一日置き[ichinichioki] every other day

１月[ichigatsu] January
ひと月[ichigetsu] one month
下弦の月[kagennotsuki] waning moon
何ヶ月[nankagetsu] how many months?
何月[nangatsu] what month

佳月[kagetsu] good month
か月[kagetsu] (number of) months
花鳥風月[kachoufuugetsu] beauties of nature
各月[kakugetsu] every month
隔月[kakugetsu] every second month

賀正[gashou] A Happy New Year!
改正[kaisei] revision
改正案[kaiseian] reform bill
規則正い[kisokutadashii] regular
旧正月[kyuushougatsu] lunisolar New Year

匡正[kyousei] reform
きょう正[kyousei] correction
憲法を改正する[kenpouwokaiseisuru] to revise the constitution
憲法改正[kenpoukaisei] constitutional reform
厳正[gensei] strictness