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

お札[osatsu] bill
ドル札[dorusatsu] dollar bill
一円札[ichiensatsu] one-yen bill
一札[issatsu] document
下げ札[sagefuda] tag

花札[hanafuda] floral playing cards
荷札[nifuda] label
改札[kaisatsu] examination of tickets
改札口[kaisatsuguchi] ticket barrier (gate)
改札鋏[kaisatsuhasami] ticket punch

１枚[ichimai] one thin flat object
一枚下[ichimaishita] one step lower
一枚貝[ichimaigai] univalve
一枚看板[ichimaikanban] (a) leading player
一枚岩[ichimaiiwa] monolith

一枚上[ichimaiue] one step higher
何枚[nanmai] how many thin flat objects?
３枚[sanmai] three flat objects (e.g. tickets, pieces of cloth, etc.)
三枚目[sanmaime] comedian
紙一枚[kamiichimai] one sheet of paper

印鑑[inkan] stamp
印鑑証明[inkanshoumei] certification of official registration of a seal
鑑みる[kangamiru] to heed
鑑札[kansatsu] licence
鑑識[kanshiki] judgement

鑑賞[kanshou] appreciation (e.g. of art)
鑑定[kantei] judgement
鑑別[kanbetsu] discrimination
龜鑑[kikan] pattern
図鑑[zukan] illustrated reference book