Update Day_20.md

Author: darkprinx

Status/Day_20.md

@@ -131,7 +131,7 @@ print(li)
 
 ### **Question**
 
->***By using list comprehension, please write a program generate a 3*5*8 3D array whose each element is 0.***
+> ***By using list comprehension, please write a program generate a 3\*5\*8 3D array whose each element is 0.***
 
 
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