一 到 九十九【yī dào jiǔshíjiǔ】

Numbers up to ninety-nine are built from the digits 一 to 九 and shí十, with one rule: a digit on the left of 十 multiplies it, a digit on the right adds to it.

十二 is ten plus two, so twelve. 二十 is two tens, so twenty. 二十五 is two tens plus five. Eleven to nineteen start straight from 十, with no 一 in front.

• × 一十五 → 十五

二 or 两

Two on its own in front of a measure word is liǎng两. Everywhere else in this range it is èr二: counting aloud, phone and room numbers, and the 2 inside 十二 or 二十二, even when a measure word follows.

• × 二个学生 → 两个学生
• × 十两个月 → 十二个月

Zero, and digit-by-digit numbers

Zero is líng零, also written 〇. Room numbers, phone numbers and years are read digit by digit, with 零 or 〇 for each zero.

Financial forms

On cheques, invoices and bank forms the digits are written 壹 贰 叁 肆 伍 陆 柒 捌 玖 拾, which are harder to alter. They are read the same way as 一 to 十.