Correct

对折

/ duìzhé / 
Strokes

Definition

to sell at a 50% discount/to fold in two

Example

As a Verb

fold once in the middle; folio

1
Bǎ
把
xìn
信
duìzhé
对折
  
。

Fold the letter in two.

2
Bǎ
把
zhè
这
zhāng
张
zhǐ
纸
duìzhé
对折
yī
一
xià
下
  
。

Please fold the paper once in the middle.

As a Noun

50% discount

3
Duìzhé
对折
chūshòu
出售

sell at a 50% discount