How to say "One" in Japanese

When translating "one" into Japanese, you must choose carefully between 億 and 一夜. In Japanese, 億 (おく (oku)) is typically associated with "one hundred million (100,000,000)" (Syllabus Level: N3) and represents A large numerical unit in Japanese. 1億 = 100,000,000. Often used for large amounts of money, population, or astronomical figures.. On the other hand, 一夜 (いちや (ichiya)) maps to "one night; all night long" (Syllabus Level: N2) and represents Refers to a single night, often implying something happened or was completed during that night, or something that lasts for one night. Can sometimes imply a sudden or dramatic change, similar to 'overnight'.. A literal translation of "one" can often sound unnatural to native Japanese speakers if mixed up!