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

ない交ぜにする[naimazenisuru] to blend (e.g. truth and lies)
データ交換[deetakoukan] data exchange
メール交換[meerukoukan] exchange of letters
リーダー交代[riidaakoutai] leadership change
意見交換[ikenkoukan] exchange of ideas

一方交通[ippoukoutsuu] one-way traffic
羽交絞め[hagaijime] pinioning
仮名交じり[kanamajiri] mixed writing (characters and kana)
仮名交じり文[kanamajiribun] mixed writing (characters and kana)
賀詞交換[gashikoukan] New Year greetings (parties)

お風呂に入る[ofuronihairu] to take a bath
鍬入れ式[kuwaireshiki] ground-breaking ceremony
塵入[gomiire] trashcan
キー入力[kiinyuuryoku] key (input)
ビジネススクール入学共通試験[bijinesusukuurunyuugakukyoutsuushiken] business school entrance test

メスを入れる[mesuwoireru] to operate
圧入[atsunyuu] indentation
移入[inyuu] importation
一寝入り[hitoneiri] nap
一入[hitoshio] still more

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)

お宮[omiya] Shinto shrine
御宮参り[omiyamairi] shrine visit
伊勢大神宮[isedaijinguu] the Grand Shrines of Ise
王宮[oukyuu] royal palace
黄道十二宮[koudoujuunikyuu] twelve signs of the zodiac

仮宮[karimiya] temporary shrine
宮崎県[miyazakiken] Miyazaki prefecture (Kyushu)
宮参り[miyamairi] shrine visit
宮司[guuji] chief priest
宮城[kyuujou] Imperial Palace