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

兎や角言う[toyakakuiu] to say all kinds of things
家兎[kato] domestic rabbit
脱兎のごとく[dattonogotoku] (at) high speed
兎にも角にも[tonimokakunimo] anyhow
兎に角[tonikaku] anyhow

兎の毛[unoke] just a hair
兎も角[tomokaku] anyhow
兎も角も[tomokakumo] anyhow
兎も有れ[tomoare] anyhow