Bài 1: A=\(\left\{H,I,N,O,C\right\}\)
Bài 2: M=\(\left\{3,4,5,6\right\}\)
Bài 3: \(A=\left\{6,23\right\}\\ B=\left\{3,u,t\right\}\\ C=\left\{cua\right\}\)
D={cua,cá,ốc}
bài 4:
C={6,7,8,9}
Bài 5:
14∉B, 9∈A, 9∈B, 0∈A
Bài 6: M={13,14,15,16}
13∈M, 19∉M, 12∉M, 16∈M