Subcases are Cases within cases, that may occur oftentimes.
Example Question
How many 4 letter ‘words’ can you make from the letters of the word URANIUM that begins with a vowel.
You must divide it into cases. Starts with a vowel, and also pay attention to the fact that there are 2 U’s.
Case 1: Starts with I Case 1.1: Starts with I AND No U Case 1.2: Starts with I AND One U Case 1.3: Starts with I AND Two U Case 2: Starts with A Case 2.1: Starts with A AND No U Case 2.2: Starts with A AND One U Case 2.3: Starts with A AND Two U Case 3: Starts with U Case 3.1: Starts with U AND One U Case 3.2: Starts with U AND Two U