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

コマ割り[komawari] panel layout
一割[ichiwari] ten percent
一割引き[ichiwaribiki] 10% off sale
学割り[gakuwari] student discount
額面割れ[gakumenware] drop below par

割く[saku] to tear
割引券[waribikiken] discount coupon or ticket
割引く[waribiku] to discount
割り栗[wariguri] rubble
割り栗石[wariguriishi] crushed rock