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

宛がう[ategau] to allot
宛てる[ateru] to address
宛ら[sanagara] just like
宛も[adakamo] as if
私宛[watashiate] my address

宛て[ate] aim
宛字[ateji] kanji used as a phonetic symbol, instead of for the meaning
一つ宛[hitotsuzutsu] one by one
宛て先[atesaki] address
宛て名[atena] (addressee's) name