one-tenth; tenth; tithe
Used for fractions, percentages, and historical or religious tithes. The reading じゅうぶんのいち is standard; note that 十分 can also be read じゅっぷん (ten minutes), so context is important.
収入の十分の一を貯金している。
I save one-tenth of my income.
この教会では十分の一税を納める習慣がある。
This church has a custom of paying a tithe.
十分 (じゅうぶん) means 'enough' or 'sufficient', while 十分の一 (じゅうぶんのいち) means 'one-tenth'. The reading is the same but the meaning is different.
Standard kanji spelling for 'one-tenth'.
Numerical spelling, common in horizontal writing and technical contexts.
Compound of 十分 (じゅうぶん, 'ten parts') + の (possessive particle) + 一 (いち, 'one'), literally 'one of ten parts'.