Question

设U={X|X是小于9的正整数},A={1,2,3},B={3,4,5,6},则CUA= ,CUB= ,

Answer 1

U={X|X是小于9的正整数}={1,2,3,4,5,6,7,8}

A={1,2,3} CUA={4,5,6,7,8}

B={3,4,5,6} CUB={1,2,7,8}