九つ[kokonotsu] nine
九夏[kyuuka] summer
九回戦[kyuukaisen] regulation game
九官鳥[kyuukanchou] hill myna (species of mynah bird, Gracula religiosa)
九牛の一毛[kyuugyuunoichimou] mere fraction

九々[kuku] multiplication table
九月[kugatsu] September
九工大[kyuukoudai] Kyushu Institute of Technology
九穀[kyuukoku] the nine grains
九死に一生[kyuushiniisshou] narrow escape from death

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