十

十 (shí) means 'ten' and is one of the first numbers every Mandarin learner memorizes. It is the gateway to all numbers above ten because Chinese builds them transparently: 十一 (eleven, 'ten-one'), 十二 (twelve, 'ten-two'), 二十 (twenty, 'two-ten'), 二十五 (twenty-five, 'two-ten-five'), and so on up to 九十九 (ninety-nine). This logical structure makes Chinese numbers far easier to learn than English's 'eleven, twelve, thirteen' irregularities. 十 also appears in dates (十月 'October'), idioms (十分 'completely / very much', literally 'ten parts'), and the formal/secure financial form 拾, used on checks to prevent forgery. Cultural note: the character 十 is a simple cross shape — sometimes mistaken by beginners for a plus sign — and is one of the most-frequent Chinese characters in everyday text.

Memory hook: 十 looks like a plus sign (+). Easy to remember: '+' means 'add', and 十 is the foundation you 'add' all other numbers onto.