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

御手玉[otedama] beanbag
御手上げ[oteage] all over
御手盛り[otemori] making arbitrary decisions which benefit oneself
御手洗い[otearai] toilet
お手伝いさん[otetsudaisan] maid

手子摺る[tekozuru] to have much trouble
引っ手繰り[hittakuri] purse snatching
悪手[akushu] poor move
握手[akushu] handshake
安手[yasude] cheap kind