Question 912435


 A complete list of the subsets of A= { 15,16,17,18,19,20} is: 

there are {{{64}}} subsets and {{{63}}} proper subsets


 {},{15},{16},{17},{18},{19},{20},{15,16},{15,17},{15,18},{15,19},{15,20},{16,17},{16,18},{16,19},{16,20},{17,18},{17,19},{17,20},{18,19},{18,20},{19,20},{15,16,17},{15,16,18},{15,16,19},{15,16,20},{15,17,18},{15,17,19},{15,17,20},{15,18,19},{15,18,20},{15,19,20},{16,17,18},{16,17,19},{16,17,20},{16,18,19},{16,18,20},{16,19,20},{17,18,19},{17,18,20},{17,19,20},{18,19,20},{15,16,17,18},{15,16,17,19},{15,16,17,20},{15,16,18,19},{15,16,18,20},{15,16,19,20},{15,17,18,19},{15,17,18,20},{15,17,19,20},{15,18,19,20},{16,17,18,19},{16,17,18,20},{16,17,19,20},{16,18,19,20},{17,18,19,20},{15,16,17,18,19},{15,16,17,18,20},{15,16,17,19,20},{15,16,18,19,20},{15,17,18,19,20},{16,17,18,19,20},{15,16,17,18,19,20}

 All of these are proper subsets of { 15,16,17,18,19,20} except for { 15,16,17,18,19,20} itself.