Let u= 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20.
Let B=3,9,12,15,,18,21,9.
Let C=3,6,12,15,18,21,9.
Let D=6,12,18,24.

answer this
1. B U C=
2.C U D=
3. B - D=
4. C - D=
5. B​