You can remember the meaning of 十分 with this easy mnemonic:
The Christmas present was <strong>ten</strong> (十) <strong>points</strong> (分) out of ten! <strong>Very</strong> good! Little did his girlfriend know the present was won at a work bingo game.
Using mnemonics to remember the meaning of Chinese characters like can have an enormous impact on how long to learn Mandarin it takes.