Although there are other ways of expressing certain kinds of fractions, like hanbun (半分、はんぶん) for 1/2 or 50%, 2/3 would be expressed as “san bun no ni” (三分の二, さんぶんのに). That is, “of three parts, two“. Actually, with Japanese grammar it’s nearly impossible to express this any other way.

Consequently, yonbun no san (of 4 parts, 3) is how 3/4ths would be expressed. Once you get the hang of it, it’s pretty simple.

There’s also another expression you should know: gobu-gobu (五分五分, ごぶごぶ), which means 5 parts/ 5 parts, or in “our” language, fifty-fifty. Remember that “juubun” (十分、じゅうぶん) assumes that the “bun” part (for divisions) is 10 parts, and therefore, 5 of 10 parts is half, or 50%, and 10 of 10 parts is all, or 100%. If you’ve put in 100% effort, that’s considered enough. If your odds are 50% success or 50% failure, they’re 50-50, or gobu-gobu.

Practice and quick processing of these words will enable you to understand the message with startling speed, allowing you to focus on other things. – J