Difference between equal sets and equivalent sets?

Answer 1

A = { 1,2,3,4,5,6 } and B = {1,2,3,4,5,6 }

A and B above are EQUAL sets because ALL their elements are precisely the SAME.

C = {a,b,c,d,e,f} and D = {3,4,5,6,7,8}

C and D are EQUIVALENT sets because the NUMBER OF ELEMENTS in both the sets is the same i.e. 6.