one-for- two split 难道不是拆分是合并？

按答案解释，貌似是one-for- two split 后股数变少了，有些困惑

if it is one-for-two stock split the total number of shares will double and the price per share will be half of the original price. 

If it is a two-for-one stock split the total number of shares will decrease to half of the original amount, the price per share will double.

但是practice volumn2 226页113题 答案说 one-for-two stock split，the total number of shares will half and the price per share will double. 

正好和一楼解释相反。