deletions | additions       diff --git a/untitled.html b/untitled.html  index f488615..83a6fb3 100644  --- a/untitled.html  +++ b/untitled.html 
...
serves fifteen entrees that contain meat, five entrees that contain fish and  three vegetarian entrees. How many dinners are there to choose from?

The rule of sum is applied  here because each entrée contains either meat or fish or is vegetarian. So we  have \(15+5+3=23.\)

• The union between two sets is denoted as \(A\cup B\). The union means that a set of objects can happen in \(A\) or \(B\) ways or even in both ways.
  
• The intersection of sets is denoted \(A\cap B\). This is the set of  objects that can happen in \(A\) and \(B\) ways.
  
• If the sets \(A\) and \(B\) have no similar elements, then \(A\cap B=\left\{\right\}\) , which is known as the empty set.
  
• The size of a set is  denoted \(\left|A\right|\) or \(\left|B\right|\) to show the amount of elements in set \(A\) or set \(B\).