Counting in a Three-Circle Diagram

Difficulty: Easy · Topics: Discrete Mathematics, Sets, Set Operations

The sets A, B and C are shown in the Venn diagram.

graph "x":[-4.5,4.5],"y":[-1.9,2.3],"axes":false,"ink":true,"label":"Three circles A, B, C in a row with elements 1–8 placed in their regions","items":["type":"circle","at":[-2.4,0],"r":1.6,"type":"circle","at":[0,0],"r":1.6,"type":"circle","at":[2.4,0],"r":1.6,"type":"label","at":[-2.4,1.95],"text":"A","type":"label","at":[0,1.95],"text":"B","type":"label","at":[2.4,1.95],"text":"C","type":"point","at":[-3.2,0.55],"label":"1","anchor":"e","italic":false,"type":"point","at":[-3.0,-0.6],"label":"2","anchor":"e","italic":false,"type":"point","at":[-1.2,-0.25],"label":"3","anchor":"n","italic":false,"type":"point","at":[0,0.7],"label":"4","anchor":"e","italic":false,"type":"point","at":[0,-0.7],"label":"5","anchor":"e","italic":false,"type":"point","at":[1.2,-0.25],"label":"6","anchor":"n","italic":false,"type":"point","at":[3.1,0.55],"label":"7","anchor":"e","italic":false,"type":"point","at":[3.1,-0.6],"label":"8","anchor":"e","italic":false]

How many elements does (Bcup C)-(Acap B) have?