math
posted by Katherine .
there are 30 students in math class.12 belong to the computer lab,and 8 belong to the photography club. 3 belong to both clubs. how many belong to neither??
please help i am confused
thank you..... :)

number( computer OR photo_
= number(computer) + number(photo)  number(computer AND photo)
= 12 + 8  3 = 17
That leaves 13 in neither of the clubs.